Home
%3CLINGO-SUB%20id%3D%22lingo-sub-347268%22%20slang%3D%22en-US%22%3EA%20Not%20So%20Common%20Root%20Cause%20for%20503%20Service%20Unavailable%3C%2FLINGO-SUB%3E%3CLINGO-BODY%20id%3D%22lingo-body-347268%22%20slang%3D%22en-US%22%3E%3CH1%20style%3D%22box-sizing%3A%20border-box%3B%20color%3A%20inherit%3B%20font-family%3A%20%26amp%3Bquot%3B%20segoe%20ui%20light%26amp%3Bquot%3B%2C%26amp%3Bquot%3Bsegoe%20ui%26amp%3Bquot%3B%2Ctahoma%2Carial%2C%26amp%3Bquot%3Bhelvetica%20neue%26amp%3Bquot%3B%2Chelvetica%2Csans-serif%3B%20font-size%3A%2036px%3B%20font-style%3A%20normal%3B%20font-variant%3A%20normal%3B%20font-weight%3A%20normal%3B%20letter-spacing%3A%20normal%3B%20line-height%3A%201.1%3B%20orphans%3A%202%3B%20text-align%3A%20left%3B%20text-decoration%3A%20none%3B%20text-indent%3A%200px%3B%20text-transform%3A%20none%3B%20-webkit-text-stroke-width%3A%200px%3B%20white-space%3A%20normal%3B%20word-spacing%3A%200px%3B%20margin%3A%2020px%200px%2010px%200px%3B%22%20id%3D%22toc-hId-1902198912%22%20id%3D%22toc-hId-1963036909%22%3ESymptoms%3C%2FH1%3E%0A%3CP%3E%26nbsp%3B%3C%2FP%3E%0A%3CP%20style%3D%22box-sizing%3A%20border-box%3B%20color%3A%20%23333333%3B%20font-family%3A%20%26amp%3Bquot%3B%20segoe%20ui%26amp%3Bquot%3B%2Ctahoma%2Carial%2C%26amp%3Bquot%3Bhelvetica%20neue%26amp%3Bquot%3B%2Chelvetica%2Csans-serif%3B%20font-size%3A%2014px%3B%20font-style%3A%20normal%3B%20font-variant%3A%20normal%3B%20font-weight%3A%20400%3B%20letter-spacing%3A%20normal%3B%20orphans%3A%202%3B%20text-align%3A%20left%3B%20text-decoration%3A%20none%3B%20text-indent%3A%200px%3B%20text-transform%3A%20none%3B%20-webkit-text-stroke-width%3A%200px%3B%20white-space%3A%20normal%3B%20word-spacing%3A%200px%3B%20margin%3A%200px%200px%2010px%200px%3B%22%3ESo%20a%20co-worker%20of%20mine%20was%20setting%20up%20IIS%207.0%20on%20a%20new%20Windows%207%20machine%2C%20and%20when%20they%20were%20browsing%20to%20http%3A%2F%2Flocalhost%20they%20were%20getting%20a%20503%20Service%20Unavailable%20error%20as%20shown%20here%3A%3C%2FP%3E%0A%3CP%3E%26nbsp%3B%3C%2FP%3E%0A%3CP%20style%3D%22box-sizing%3A%20border-box%3B%20color%3A%20%23333333%3B%20font-family%3A%20%26amp%3Bquot%3B%20segoe%20ui%26amp%3Bquot%3B%2Ctahoma%2Carial%2C%26amp%3Bquot%3Bhelvetica%20neue%26amp%3Bquot%3B%2Chelvetica%2Csans-serif%3B%20font-size%3A%2014px%3B%20font-style%3A%20normal%3B%20font-variant%3A%20normal%3B%20font-weight%3A%20400%3B%20letter-spacing%3A%20normal%3B%20orphans%3A%202%3B%20text-align%3A%20left%3B%20text-decoration%3A%20none%3B%20text-indent%3A%200px%3B%20text-transform%3A%20none%3B%20-webkit-text-stroke-width%3A%200px%3B%20white-space%3A%20normal%3B%20word-spacing%3A%200px%3B%20margin%3A%200px%200px%2010px%200px%3B%22%3E%3CIMG%20width%3D%22346%22%20height%3D%22168%22%20title%3D%22503%20Service%20Unavailable%22%20style%3D%22border-image-outset%3A%200%3B%20border-image-repeat%3A%20stretch%3B%20border-image-slice%3A%20100%25%3B%20border-image-source%3A%20none%3B%20border-image-width%3A%201%3B%20box-sizing%3A%20border-box%3B%20height%3A%20168px%3B%20max-width%3A%20100%25%3B%20vertical-align%3A%20middle%3B%20width%3A%20346px%3B%20border%3A%200px%20none%20currentColor%3B%22%20alt%3D%22503%20Service%20Unavailable%22%20src%3D%22https%3A%2F%2Fmsdnshared.blob.core.windows.net%2Fmedia%2FMSDNBlogsFS%2Fprod.evol.blogs.msdn.com%2FCommunityServer.Components.PostAttachments%2F00%2F09%2F96%2F51%2F87%2FServiceUnavailable.PNG%22%20border%3D%220%22%20%2F%3E%3C%2FP%3E%0A%3CP%3E%26nbsp%3B%3C%2FP%3E%0A%3CH1%20style%3D%22box-sizing%3A%20border-box%3B%20color%3A%20inherit%3B%20font-family%3A%20%26amp%3Bquot%3B%20segoe%20ui%20light%26amp%3Bquot%3B%2C%26amp%3Bquot%3Bsegoe%20ui%26amp%3Bquot%3B%2Ctahoma%2Carial%2C%26amp%3Bquot%3Bhelvetica%20neue%26amp%3Bquot%3B%2Chelvetica%2Csans-serif%3B%20font-size%3A%2036px%3B%20font-style%3A%20normal%3B%20font-variant%3A%20normal%3B%20font-weight%3A%20normal%3B%20letter-spacing%3A%20normal%3B%20line-height%3A%201.1%3B%20orphans%3A%202%3B%20text-align%3A%20left%3B%20text-decoration%3A%20none%3B%20text-indent%3A%200px%3B%20text-transform%3A%20none%3B%20-webkit-text-stroke-width%3A%200px%3B%20white-space%3A%20normal%3B%20word-spacing%3A%200px%3B%20margin%3A%2020px%200px%2010px%200px%3B%22%20id%3D%22toc-hId--649958049%22%20id%3D%22toc-hId--589120052%22%3ETroubleshooting%3C%2FH1%3E%0A%3CP%3E%26nbsp%3B%3C%2FP%3E%0A%3CP%20style%3D%22box-sizing%3A%20border-box%3B%20color%3A%20%23333333%3B%20font-family%3A%20%26amp%3Bquot%3B%20segoe%20ui%26amp%3Bquot%3B%2Ctahoma%2Carial%2C%26amp%3Bquot%3Bhelvetica%20neue%26amp%3Bquot%3B%2Chelvetica%2Csans-serif%3B%20font-size%3A%2014px%3B%20font-style%3A%20normal%3B%20font-variant%3A%20normal%3B%20font-weight%3A%20400%3B%20letter-spacing%3A%20normal%3B%20orphans%3A%202%3B%20text-align%3A%20left%3B%20text-decoration%3A%20none%3B%20text-indent%3A%200px%3B%20text-transform%3A%20none%3B%20-webkit-text-stroke-width%3A%200px%3B%20white-space%3A%20normal%3B%20word-spacing%3A%200px%3B%20margin%3A%200px%200px%2010px%200px%3B%22%3EThis%20seemed%20pretty%20trivial%20so%20I%20went%20through%20the%20following%20checklist.%3C%2FP%3E%0A%3CP%3E%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%20color%3A%20%23333333%3B%20font-family%3A%20%26amp%3Bquot%3B%20segoe%20ui%26amp%3Bquot%3B%2Ctahoma%2Carial%2C%26amp%3Bquot%3Bhelvetica%20neue%26amp%3Bquot%3B%2Chelvetica%2Csans-serif%3B%20font-size%3A%2014px%3B%20font-style%3A%20normal%3B%20font-variant%3A%20normal%3B%20font-weight%3A%20400%3B%20letter-spacing%3A%20normal%3B%20orphans%3A%202%3B%20text-align%3A%20left%3B%20text-decoration%3A%20none%3B%20text-indent%3A%200px%3B%20text-transform%3A%20none%3B%20-webkit-text-stroke-width%3A%200px%3B%20white-space%3A%20normal%3B%20word-spacing%3A%200px%3B%22%20%2F%3E%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3E%3CLI-WRAPPER%3E%3C%2FLI-WRAPPER%3E%3C%2FP%3E%0A%3CUL%3E%0A%3CLI%20style%3D%22box-sizing%3A%20border-box%3B%22%3EIs%20W3SVC%20started%3F%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%20Yes%3C%2FLI%3E%0A%3C%2FUL%3E%0A%3CP%3E%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3E%3CLI-WRAPPER%3E%0A%3C%2FLI-WRAPPER%3E%3C%2FP%3E%3CLI%20style%3D%22box-sizing%3A%20border-box%3B%22%3EIs%20the%20Default%20Web%20Site%20started%3F%26nbsp%3B%26nbsp%3B%20Yes%3C%2FLI%3E%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3E%3CLI-WRAPPER%3E%0A%3CLI%20style%3D%22box-sizing%3A%20border-box%3B%22%3EIs%20the%20Application%20Pool%20Disabled%3F%26nbsp%3B%20No%3C%2FLI%3E%0A%3C%2FLI-WRAPPER%3E%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3E%3CLI-WRAPPER%3E%0A%3CLI%20style%3D%22box-sizing%3A%20border-box%3B%22%3EIs%20the%20Application%20Pool%20Started%3F%26nbsp%3B%26nbsp%3B%20Yes%3C%2FLI%3E%0A%3C%2FLI-WRAPPER%3E%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3E%3CLI-WRAPPER%3E%0A%3CLI%20style%3D%22box-sizing%3A%20border-box%3B%22%3EIs%20the%20w3wp.exe%20process%20for%20the%20application%20running%3F%26nbsp%3B%20No%3C%2FLI%3E%0A%3C%2FLI-WRAPPER%3E%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3E%3CLI-WRAPPER%3E%0A%3CLI%20style%3D%22box-sizing%3A%20border-box%3B%22%3EAre%20their%20any%20WAS%20or%20W3SVC%20Events%20in%20the%20Application%20or%20System%20Event%20logs%3F%26nbsp%3B%20No%3C%2FLI%3E%0A%3C%2FLI-WRAPPER%3E%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3E%3CLI-WRAPPER%3E%0A%3CLI%20style%3D%22box-sizing%3A%20border-box%3B%22%3EAre%20their%20any%20entries%20in%20the%20IIS%20Log%20for%20the%20web%20site%3F%26nbsp%3B%20No%3C%2FLI%3E%0A%3C%2FLI-WRAPPER%3E%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3E%3CLI-WRAPPER%3E%0A%3COL%20style%3D%22box-sizing%3A%20border-box%3B%20color%3A%20%23333333%3B%20font-family%3A%20%26amp%3Bquot%3B%20segoe%20ui%26amp%3Bquot%3B%2Ctahoma%2Carial%2C%26amp%3Bquot%3Bhelvetica%20neue%26amp%3Bquot%3B%2Chelvetica%2Csans-serif%3B%20font-size%3A%2014px%3B%20font-style%3A%20normal%3B%20font-variant%3A%20normal%3B%20font-weight%3A%20400%3B%20letter-spacing%3A%20normal%3B%20margin-bottom%3A%2010px%3B%20margin-top%3A%200px%3B%20orphans%3A%202%3B%20text-align%3A%20left%3B%20text-decoration%3A%20none%3B%20text-indent%3A%200px%3B%20text-transform%3A%20none%3B%20-webkit-text-stroke-width%3A%200px%3B%20white-space%3A%20normal%3B%20word-spacing%3A%200px%3B%22%3E%0A%3CLI%20style%3D%22box-sizing%3A%20border-box%3B%22%3EAre%20their%20any%20entries%20in%20the%20HTTP%20error%20logs%3F%26nbsp%3B%26nbsp%3B%20Yes%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3E%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3E%3CP%20class%3D%22code%22%20style%3D%22box-sizing%3A%20border-box%3B%20margin%3A%200px%200px%2010px%200px%3B%22%3E2010-02-17%2017%3A28%3A47%20%3A%3A1%250%2049991%20%3A%3A1%250%2080%20HTTP%2F1.1%20GET%20%2F%20503%20-%20N%2FA%20-%3C%2FP%3E%0A%3C%2FLI%3E%0A%3C%2FOL%3E%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%20color%3A%20%23333333%3B%20font-family%3A%20%26amp%3Bquot%3B%20segoe%20ui%26amp%3Bquot%3B%2Ctahoma%2Carial%2C%26amp%3Bquot%3Bhelvetica%20neue%26amp%3Bquot%3B%2Chelvetica%2Csans-serif%3B%20font-size%3A%2014px%3B%20font-style%3A%20normal%3B%20font-variant%3A%20normal%3B%20font-weight%3A%20400%3B%20letter-spacing%3A%20normal%3B%20orphans%3A%202%3B%20text-align%3A%20left%3B%20text-decoration%3A%20none%3B%20text-indent%3A%200px%3B%20text-transform%3A%20none%3B%20-webkit-text-stroke-width%3A%200px%3B%20white-space%3A%20normal%3B%20word-spacing%3A%200px%3B%22%20%2F%3E%3CP%20style%3D%22box-sizing%3A%20border-box%3B%20color%3A%20%23333333%3B%20font-family%3A%20%26amp%3Bquot%3B%20segoe%20ui%26amp%3Bquot%3B%2Ctahoma%2Carial%2C%26amp%3Bquot%3Bhelvetica%20neue%26amp%3Bquot%3B%2Chelvetica%2Csans-serif%3B%20font-size%3A%2014px%3B%20font-style%3A%20normal%3B%20font-variant%3A%20normal%3B%20font-weight%3A%20400%3B%20letter-spacing%3A%20normal%3B%20orphans%3A%202%3B%20text-align%3A%20left%3B%20text-decoration%3A%20none%3B%20text-indent%3A%200px%3B%20text-transform%3A%20none%3B%20-webkit-text-stroke-width%3A%200px%3B%20white-space%3A%20normal%3B%20word-spacing%3A%200px%3B%20margin%3A%200px%200px%2010px%200px%3B%22%3ESo%20what%20could%20be%20going%20on%20here%3F%20After%20a%20bit%20of%20troubleshooting%20I%20was%20able%20to%20find%20a%20event%20in%20the%20event%20log%20that%20led%20me%20in%20the%20correct%20direction.%20Here%20is%20a%20summary%20of%20the%20event%3A%3C%2FP%3E%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%20color%3A%20%23333333%3B%20font-family%3A%20%26amp%3Bquot%3B%20segoe%20ui%26amp%3Bquot%3B%2Ctahoma%2Carial%2C%26amp%3Bquot%3Bhelvetica%20neue%26amp%3Bquot%3B%2Chelvetica%2Csans-serif%3B%20font-size%3A%2014px%3B%20font-style%3A%20normal%3B%20font-variant%3A%20normal%3B%20font-weight%3A%20400%3B%20letter-spacing%3A%20normal%3B%20orphans%3A%202%3B%20text-align%3A%20left%3B%20text-decoration%3A%20none%3B%20text-indent%3A%200px%3B%20text-transform%3A%20none%3B%20-webkit-text-stroke-width%3A%200px%3B%20white-space%3A%20normal%3B%20word-spacing%3A%200px%3B%22%20%2F%3E%3CP%20class%3D%22error%22%20style%3D%22box-sizing%3A%20border-box%3B%20color%3A%20%23333333%3B%20font-family%3A%20%26amp%3Bquot%3B%20segoe%20ui%26amp%3Bquot%3B%2Ctahoma%2Carial%2C%26amp%3Bquot%3Bhelvetica%20neue%26amp%3Bquot%3B%2Chelvetica%2Csans-serif%3B%20font-size%3A%2014px%3B%20font-style%3A%20normal%3B%20font-variant%3A%20normal%3B%20font-weight%3A%20400%3B%20letter-spacing%3A%20normal%3B%20orphans%3A%202%3B%20text-align%3A%20left%3B%20text-decoration%3A%20none%3B%20text-indent%3A%200px%3B%20text-transform%3A%20none%3B%20-webkit-text-stroke-width%3A%200px%3B%20white-space%3A%20normal%3B%20word-spacing%3A%200px%3B%20margin%3A%200px%200px%2010px%200px%3B%22%3ELog%20Name%3A%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%20System%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3ESource%3A%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%20Microsoft-Windows-HttpEvent%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3EDate%3A%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%202%2F17%2F2010%209%3A26%3A44%20AM%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3EEvent%20ID%3A%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%2015007%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3ETask%20Category%3A%20None%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3ELevel%3A%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%20Information%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3EKeywords%3A%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%20Classic%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3EUser%3A%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%20N%2FA%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3EComputer%3A%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%20computer.domain.com%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3EDescription%3A%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3EReservation%20for%20namespace%20identified%20by%20URL%20prefix%20http%3A%2F%2F%2B%3A80%2F%20was%20successfully%20added.%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3EEvent%20Xml%3A%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3E%3CEVENT%20xmlns%3D%22%26lt%3BA%22%20href%3D%22http%3A%2F%2Fschemas.microsoft.com%2Fwin%2F2004%2F08%2Fevents%2Fevent%22%20target%3D%22_blank%22%20rel%3D%22noopener%20noreferrer%22%3E%3CA%20href%3D%22http%3A%2F%2Fschemas.microsoft.com%2Fwin%2F2004%2F08%2Fevents%2Fevent%22%20target%3D%22_blank%22%20rel%3D%22noopener%20noreferrer%22%3Ehttp%3A%2F%2Fschemas.microsoft.com%2Fwin%2F2004%2F08%2Fevents%2Fevent%3C%2FA%3E%22%26gt%3B%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3E%26nbsp%3B%20%3CSYSTEM%3E%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3E%26nbsp%3B%26nbsp%3B%26nbsp%3B%20%3CPROVIDER%20name%3D%22%26quot%3BMicrosoft-Windows-HttpEvent%26quot%3B%22%20guid%3D%22%26quot%3B%7B7b6bc78c-898b-4170-bbf8-1a469ea43fc5%7D%26quot%3B%22%20eventsourcename%3D%22%26quot%3BHTTP%26quot%3B%22%3E%3C%2FPROVIDER%3E%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3E%26nbsp%3B%26nbsp%3B%26nbsp%3B%20%3CEVENTID%20qualifiers%3D%22%26quot%3B16384%26quot%3B%22%3E15007%3C%2FEVENTID%3E%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3E%26nbsp%3B%26nbsp%3B%26nbsp%3B%20%3CVERSION%3E0%3C%2FVERSION%3E%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3E%26nbsp%3B%26nbsp%3B%26nbsp%3B%20%3CLEVEL%3E4%3C%2FLEVEL%3E%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3E%26nbsp%3B%26nbsp%3B%26nbsp%3B%20%3CTASK%3E0%3C%2FTASK%3E%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3E%26nbsp%3B%26nbsp%3B%26nbsp%3B%20%3COPCODE%3E0%3C%2FOPCODE%3E%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3E%26nbsp%3B%26nbsp%3B%26nbsp%3B%20%3CKEYWORDS%3E0x80000000000000%3C%2FKEYWORDS%3E%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3E%26nbsp%3B%26nbsp%3B%26nbsp%3B%20%3CTIMECREATED%20systemtime%3D%22%26quot%3B2010-02-17T17%3A26%3A44.064479100Z%26quot%3B%22%3E%3C%2FTIMECREATED%3E%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3E%26nbsp%3B%26nbsp%3B%26nbsp%3B%20%3CEVENTRECORDID%3E42570%3C%2FEVENTRECORDID%3E%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3E%26nbsp%3B%26nbsp%3B%26nbsp%3B%20%3CCORRELATION%3E%3C%2FCORRELATION%3E%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3E%26nbsp%3B%26nbsp%3B%26nbsp%3B%20%3CEXECUTION%20processid%3D%22%26quot%3B4%26quot%3B%22%20threadid%3D%22%26quot%3B44%26quot%3B%22%3E%3C%2FEXECUTION%3E%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3E%26nbsp%3B%26nbsp%3B%26nbsp%3B%20%3CCHANNEL%3ESystem%3C%2FCHANNEL%3E%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3E%26nbsp%3B%26nbsp%3B%26nbsp%3B%20%3CCOMPUTER%3Ecomputer.domain.com%3C%2FCOMPUTER%3E%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3E%26nbsp%3B%26nbsp%3B%26nbsp%3B%20%3CSECURITY%3E%3C%2FSECURITY%3E%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3E%26nbsp%3B%20%3C%2FSYSTEM%3E%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3E%26nbsp%3B%20%3CEVENTDATA%3E%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3E%26nbsp%3B%26nbsp%3B%26nbsp%3B%20%3CDATA%20name%3D%22%26quot%3BDeviceObject%26quot%3B%22%3E%5CDevice%5CHttp%5CReqQueue%3C%2FDATA%3E%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3E%26nbsp%3B%26nbsp%3B%26nbsp%3B%20%3CDATA%20name%3D%22%26quot%3BUrl%26quot%3B%22%3Ehttp%3A%2F%2F%2B%3A80%2F%3C%2FDATA%3E%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3E%26nbsp%3B%20%3C%2FEVENTDATA%3E%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3E%3C%2FEVENT%3E%3C%2FP%3E%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%20color%3A%20%23333333%3B%20font-family%3A%20%26amp%3Bquot%3B%20segoe%20ui%26amp%3Bquot%3B%2Ctahoma%2Carial%2C%26amp%3Bquot%3Bhelvetica%20neue%26amp%3Bquot%3B%2Chelvetica%2Csans-serif%3B%20font-size%3A%2014px%3B%20font-style%3A%20normal%3B%20font-variant%3A%20normal%3B%20font-weight%3A%20400%3B%20letter-spacing%3A%20normal%3B%20orphans%3A%202%3B%20text-align%3A%20left%3B%20text-decoration%3A%20none%3B%20text-indent%3A%200px%3B%20text-transform%3A%20none%3B%20-webkit-text-stroke-width%3A%200px%3B%20white-space%3A%20normal%3B%20word-spacing%3A%200px%3B%22%20%2F%3E%3CP%20style%3D%22box-sizing%3A%20border-box%3B%20color%3A%20%23333333%3B%20font-family%3A%20%26amp%3Bquot%3B%20segoe%20ui%26amp%3Bquot%3B%2Ctahoma%2Carial%2C%26amp%3Bquot%3Bhelvetica%20neue%26amp%3Bquot%3B%2Chelvetica%2Csans-serif%3B%20font-size%3A%2014px%3B%20font-style%3A%20normal%3B%20font-variant%3A%20normal%3B%20font-weight%3A%20400%3B%20letter-spacing%3A%20normal%3B%20orphans%3A%202%3B%20text-align%3A%20left%3B%20text-decoration%3A%20none%3B%20text-indent%3A%200px%3B%20text-transform%3A%20none%3B%20-webkit-text-stroke-width%3A%200px%3B%20white-space%3A%20normal%3B%20word-spacing%3A%200px%3B%20margin%3A%200px%200px%2010px%200px%3B%22%3EThe%20key%20part%20of%20this%20event%20is%20that%20it%20mentions%20the%20namespace%20http%3A%2F%2F%2B%3A80%2F%20was%20successfully%20added.%20What%20exactly%20does%20this%20mean%3F%20I%20am%20not%20going%20to%20go%20into%20detail%20in%20this%20blog%2C%20but%20%3CA%20style%3D%22background-color%3A%20transparent%3B%20box-sizing%3A%20border-box%3B%20color%3A%20%23337ab7%3B%20text-decoration%3A%20none%3B%22%20href%3D%22http%3A%2F%2Fblogs.msdn.com%2Fdrnick%2Farchive%2F2006%2F10%2F16%2Fconfiguring-http-for-windows-vista.aspx%22%20target%3D%22_blank%22%20rel%3D%22noopener%20noreferrer%20noopener%20noreferrer%22%3Ethis%3C%2FA%3E%26nbsp%3Bblog%20explains%20why%20URL%20reservations%26nbsp%3Bare%20typically%20used.%26nbsp%3B%20In%20our%20case%20we%20first%20need%20to%20list%20all%20of%20the%20registered%20URLs%20via%20the%20following%20command%2C%20run%20from%20an%20Administrative%20command%20prompt.%3C%2FP%3E%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%20color%3A%20%23333333%3B%20font-family%3A%20%26amp%3Bquot%3B%20segoe%20ui%26amp%3Bquot%3B%2Ctahoma%2Carial%2C%26amp%3Bquot%3Bhelvetica%20neue%26amp%3Bquot%3B%2Chelvetica%2Csans-serif%3B%20font-size%3A%2014px%3B%20font-style%3A%20normal%3B%20font-variant%3A%20normal%3B%20font-weight%3A%20400%3B%20letter-spacing%3A%20normal%3B%20orphans%3A%202%3B%20text-align%3A%20left%3B%20text-decoration%3A%20none%3B%20text-indent%3A%200px%3B%20text-transform%3A%20none%3B%20-webkit-text-stroke-width%3A%200px%3B%20white-space%3A%20normal%3B%20word-spacing%3A%200px%3B%22%20%2F%3E%3CP%20class%3D%22code%22%20style%3D%22box-sizing%3A%20border-box%3B%20color%3A%20%23333333%3B%20font-family%3A%20%26amp%3Bquot%3B%20segoe%20ui%26amp%3Bquot%3B%2Ctahoma%2Carial%2C%26amp%3Bquot%3Bhelvetica%20neue%26amp%3Bquot%3B%2Chelvetica%2Csans-serif%3B%20font-size%3A%2014px%3B%20font-style%3A%20normal%3B%20font-variant%3A%20normal%3B%20font-weight%3A%20400%3B%20letter-spacing%3A%20normal%3B%20orphans%3A%202%3B%20text-align%3A%20left%3B%20text-decoration%3A%20none%3B%20text-indent%3A%200px%3B%20text-transform%3A%20none%3B%20-webkit-text-stroke-width%3A%200px%3B%20white-space%3A%20normal%3B%20word-spacing%3A%200px%3B%20margin%3A%200px%200px%2010px%200px%3B%22%3Enetsh%20http%20show%20urlacl%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3E%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3EReserved%20URL%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%20%3A%20http%3A%2F%2F%2B%3A80%2F%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3E%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%20User%3A%20NT%20SERVICE%5CMachine%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3E%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%20Listen%3A%20Yes%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3E%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%20Delegate%3A%20No%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3E%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%26nbsp%3B%20SDDL%3A%20D%3A(A%3B%3BGX%3B%3B%3BS-1-5-21-2127521184-1604012920-1887927527-67210)%3C%2FP%3E%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%20color%3A%20%23333333%3B%20font-family%3A%20%26amp%3Bquot%3B%20segoe%20ui%26amp%3Bquot%3B%2Ctahoma%2Carial%2C%26amp%3Bquot%3Bhelvetica%20neue%26amp%3Bquot%3B%2Chelvetica%2Csans-serif%3B%20font-size%3A%2014px%3B%20font-style%3A%20normal%3B%20font-variant%3A%20normal%3B%20font-weight%3A%20400%3B%20letter-spacing%3A%20normal%3B%20orphans%3A%202%3B%20text-align%3A%20left%3B%20text-decoration%3A%20none%3B%20text-indent%3A%200px%3B%20text-transform%3A%20none%3B%20-webkit-text-stroke-width%3A%200px%3B%20white-space%3A%20normal%3B%20word-spacing%3A%200px%3B%22%20%2F%3E%3CH1%20style%3D%22box-sizing%3A%20border-box%3B%20color%3A%20inherit%3B%20font-family%3A%20%26amp%3Bquot%3B%20segoe%20ui%20light%26amp%3Bquot%3B%2C%26amp%3Bquot%3Bsegoe%20ui%26amp%3Bquot%3B%2Ctahoma%2Carial%2C%26amp%3Bquot%3Bhelvetica%20neue%26amp%3Bquot%3B%2Chelvetica%2Csans-serif%3B%20font-size%3A%2036px%3B%20font-style%3A%20normal%3B%20font-variant%3A%20normal%3B%20font-weight%3A%20normal%3B%20letter-spacing%3A%20normal%3B%20line-height%3A%201.1%3B%20orphans%3A%202%3B%20text-align%3A%20left%3B%20text-decoration%3A%20none%3B%20text-indent%3A%200px%3B%20text-transform%3A%20none%3B%20-webkit-text-stroke-width%3A%200px%3B%20white-space%3A%20normal%3B%20word-spacing%3A%200px%3B%20margin%3A%2020px%200px%2010px%200px%3B%22%20id%3D%22toc-hId-1092852286%22%20id%3D%22toc-hId-1153690283%22%3ERoot%20Cause%20%26amp%3B%20Solution%3C%2FH1%3E%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%20color%3A%20%23333333%3B%20font-family%3A%20%26amp%3Bquot%3B%20segoe%20ui%26amp%3Bquot%3B%2Ctahoma%2Carial%2C%26amp%3Bquot%3Bhelvetica%20neue%26amp%3Bquot%3B%2Chelvetica%2Csans-serif%3B%20font-size%3A%2014px%3B%20font-style%3A%20normal%3B%20font-variant%3A%20normal%3B%20font-weight%3A%20400%3B%20letter-spacing%3A%20normal%3B%20orphans%3A%202%3B%20text-align%3A%20left%3B%20text-decoration%3A%20none%3B%20text-indent%3A%200px%3B%20text-transform%3A%20none%3B%20-webkit-text-stroke-width%3A%200px%3B%20white-space%3A%20normal%3B%20word-spacing%3A%200px%3B%22%20%2F%3E%3CP%20style%3D%22box-sizing%3A%20border-box%3B%20color%3A%20%23333333%3B%20font-family%3A%20%26amp%3Bquot%3B%20segoe%20ui%26amp%3Bquot%3B%2Ctahoma%2Carial%2C%26amp%3Bquot%3Bhelvetica%20neue%26amp%3Bquot%3B%2Chelvetica%2Csans-serif%3B%20font-size%3A%2014px%3B%20font-style%3A%20normal%3B%20font-variant%3A%20normal%3B%20font-weight%3A%20400%3B%20letter-spacing%3A%20normal%3B%20orphans%3A%202%3B%20text-align%3A%20left%3B%20text-decoration%3A%20none%3B%20text-indent%3A%200px%3B%20text-transform%3A%20none%3B%20-webkit-text-stroke-width%3A%200px%3B%20white-space%3A%20normal%3B%20word-spacing%3A%200px%3B%20margin%3A%200px%200px%2010px%200px%3B%22%3EWe%20can%20see%20that%20the%20URL%20is%20reserved.%20The%20%22%2B%22%20sign%20means%20any%20host%20header%2C%20and%20the%20%3A80%20means%20anything%20on%20port%2080.%20Since%20there%20is%20no%20application%20path%20after%20the%20final%20%22%2F%22%20it%20reserves%20anything%20that%20runs%20on%20port%2080.%20This%20is%20what%20is%20causing%20the%20503%20Service%20Unavailable%20errors%2C%20as%20this%20reservation%20will%20prevent%26nbsp%3BW3SVC%20from%20obtaining%20the%20rights%20to%20listen%20on%20port%2080%20when%26nbsp%3Bit%20tries%20to%20start%20the%20site.%26nbsp%3BFurthermore%2C%20applications%20that%20run%20in%20IIS%20do%20not%20need%20explicit%20reservations%20to%20run%2C%20only%20non-IIS%20applications%20have%20to%20reserve%20a%20URL%20namespace%20if%20they%20want%20to%20use%20HTTP%20to%20listen%20for%20requests.%26nbsp%3B%20One%20example%20are%20WCF%20applications%20that%20are%20running%20on%20HTTP%2C%20as%20these%20are%20non-IIS%20applications%20that%20use%20HTTP%20to%20listen%20for%20requests.%26nbsp%3B%26nbsp%3B%20To%20resolve%20the%20problem%20for%20the%20default%20web%20site%2C%20we%20have%20to%20remove%20the%20reserved%20namespace%20for%20port%2080%20with%20the%20following%20command.%3C%2FP%3E%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%20color%3A%20%23333333%3B%20font-family%3A%20%26amp%3Bquot%3B%20segoe%20ui%26amp%3Bquot%3B%2Ctahoma%2Carial%2C%26amp%3Bquot%3Bhelvetica%20neue%26amp%3Bquot%3B%2Chelvetica%2Csans-serif%3B%20font-size%3A%2014px%3B%20font-style%3A%20normal%3B%20font-variant%3A%20normal%3B%20font-weight%3A%20400%3B%20letter-spacing%3A%20normal%3B%20orphans%3A%202%3B%20text-align%3A%20left%3B%20text-decoration%3A%20none%3B%20text-indent%3A%200px%3B%20text-transform%3A%20none%3B%20-webkit-text-stroke-width%3A%200px%3B%20white-space%3A%20normal%3B%20word-spacing%3A%200px%3B%22%20%2F%3E%3CP%20class%3D%22code%22%20style%3D%22box-sizing%3A%20border-box%3B%20color%3A%20%23333333%3B%20font-family%3A%20%26amp%3Bquot%3B%20segoe%20ui%26amp%3Bquot%3B%2Ctahoma%2Carial%2C%26amp%3Bquot%3Bhelvetica%20neue%26amp%3Bquot%3B%2Chelvetica%2Csans-serif%3B%20font-size%3A%2014px%3B%20font-style%3A%20normal%3B%20font-variant%3A%20normal%3B%20font-weight%3A%20400%3B%20letter-spacing%3A%20normal%3B%20orphans%3A%202%3B%20text-align%3A%20left%3B%20text-decoration%3A%20none%3B%20text-indent%3A%200px%3B%20text-transform%3A%20none%3B%20-webkit-text-stroke-width%3A%200px%3B%20white-space%3A%20normal%3B%20word-spacing%3A%200px%3B%20margin%3A%200px%200px%2010px%200px%3B%22%3Enetsh%20http%20delete%20urlacl%20http%3A%2F%2F%2B%3A80%2F%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3E%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%22%20%2F%3EURL%20reservation%20successfully%20deleted%3C%2FP%3E%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%20color%3A%20%23333333%3B%20font-family%3A%20%26amp%3Bquot%3B%20segoe%20ui%26amp%3Bquot%3B%2Ctahoma%2Carial%2C%26amp%3Bquot%3Bhelvetica%20neue%26amp%3Bquot%3B%2Chelvetica%2Csans-serif%3B%20font-size%3A%2014px%3B%20font-style%3A%20normal%3B%20font-variant%3A%20normal%3B%20font-weight%3A%20400%3B%20letter-spacing%3A%20normal%3B%20orphans%3A%202%3B%20text-align%3A%20left%3B%20text-decoration%3A%20none%3B%20text-indent%3A%200px%3B%20text-transform%3A%20none%3B%20-webkit-text-stroke-width%3A%200px%3B%20white-space%3A%20normal%3B%20word-spacing%3A%200px%3B%22%20%2F%3E%3CP%20class%3D%22code%22%20style%3D%22box-sizing%3A%20border-box%3B%20color%3A%20%23333333%3B%20font-family%3A%20%26amp%3Bquot%3B%20segoe%20ui%26amp%3Bquot%3B%2Ctahoma%2Carial%2C%26amp%3Bquot%3Bhelvetica%20neue%26amp%3Bquot%3B%2Chelvetica%2Csans-serif%3B%20font-size%3A%2014px%3B%20font-style%3A%20normal%3B%20font-variant%3A%20normal%3B%20font-weight%3A%20400%3B%20letter-spacing%3A%20normal%3B%20orphans%3A%202%3B%20text-align%3A%20left%3B%20text-decoration%3A%20none%3B%20text-indent%3A%200px%3B%20text-transform%3A%20none%3B%20-webkit-text-stroke-width%3A%200px%3B%20white-space%3A%20normal%3B%20word-spacing%3A%200px%3B%20margin%3A%200px%200px%2010px%200px%3B%22%3EAfter%20removing%20this%20namespace%2C%20WCF%20applications%20or%20other%20non-IIS%20applications%20running%20on%20this%20server%20may%20break.%26nbsp%3B%20So%20a%20new%20URL%20reservation%20may%20be%20needed%20for%20those%20applications.%26nbsp%3B%20The%20new%20URL%20reservation%20should%20point%20to%20the%20specific%20application%20on%20port%2080%2C%20not%20the%20root.%26nbsp%3B%20This%20will%20prevent%20the%20URL%20reservation%20from%20blocking%20all%20applications%20under%20port%2080.%26nbsp%3B%20The%20next%20question%20is%20who%20added%20the%20namespace%20in%20the%20first%20place%3F%26nbsp%3B%20There%20is%20no%20real%20way%20to%20identify%20that%2C%20however%20the%20HTTPEvent%2015007%20in%20the%20System%20Event%20log%20will%20give%20a%20good%20indication%20of%20the%20Date%20and%20Time%20the%20reservation%20was%20made.%3C%2FP%3E%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%20color%3A%20%23333333%3B%20font-family%3A%20%26amp%3Bquot%3B%20segoe%20ui%26amp%3Bquot%3B%2Ctahoma%2Carial%2C%26amp%3Bquot%3Bhelvetica%20neue%26amp%3Bquot%3B%2Chelvetica%2Csans-serif%3B%20font-size%3A%2014px%3B%20font-style%3A%20normal%3B%20font-variant%3A%20normal%3B%20font-weight%3A%20400%3B%20letter-spacing%3A%20normal%3B%20orphans%3A%202%3B%20text-align%3A%20left%3B%20text-decoration%3A%20none%3B%20text-indent%3A%200px%3B%20text-transform%3A%20none%3B%20-webkit-text-stroke-width%3A%200px%3B%20white-space%3A%20normal%3B%20word-spacing%3A%200px%3B%22%20%2F%3E%3CH1%20style%3D%22box-sizing%3A%20border-box%3B%20color%3A%20inherit%3B%20font-family%3A%20%26amp%3Bquot%3B%20segoe%20ui%20light%26amp%3Bquot%3B%2C%26amp%3Bquot%3Bsegoe%20ui%26amp%3Bquot%3B%2Ctahoma%2Carial%2C%26amp%3Bquot%3Bhelvetica%20neue%26amp%3Bquot%3B%2Chelvetica%2Csans-serif%3B%20font-size%3A%2036px%3B%20font-style%3A%20normal%3B%20font-variant%3A%20normal%3B%20font-weight%3A%20normal%3B%20letter-spacing%3A%20normal%3B%20line-height%3A%201.1%3B%20orphans%3A%202%3B%20text-align%3A%20left%3B%20text-decoration%3A%20none%3B%20text-indent%3A%200px%3B%20text-transform%3A%20none%3B%20-webkit-text-stroke-width%3A%200px%3B%20white-space%3A%20normal%3B%20word-spacing%3A%200px%3B%20margin%3A%2020px%200px%2010px%200px%3B%22%20id%3D%22toc-hId--1459304675%22%20id%3D%22toc-hId--1398466678%22%3EConclusions%3C%2FH1%3E%3CBR%20style%3D%22box-sizing%3A%20border-box%3B%20color%3A%20%23333333%3B%20font-family%3A%20%26amp%3Bquot%3B%20segoe%20ui%26amp%3Bquot%3B%2Ctahoma%2Carial%2C%26amp%3Bquot%3Bhelvetica%20neue%26amp%3Bquot%3B%2Chelvetica%2Csans-serif%3B%20font-size%3A%2014px%3B%20font-style%3A%20normal%3B%20font-variant%3A%20normal%3B%20font-weight%3A%20400%3B%20letter-spacing%3A%20normal%3B%20orphans%3A%202%3B%20text-align%3A%20left%3B%20text-decoration%3A%20none%3B%20text-indent%3A%200px%3B%20text-transform%3A%20none%3B%20-webkit-text-stroke-width%3A%200px%3B%20white-space%3A%20normal%3B%20word-spacing%3A%200px%3B%22%20%2F%3E%3CP%20style%3D%22box-sizing%3A%20border-box%3B%20color%3A%20%23333333%3B%20font-family%3A%20%26amp%3Bquot%3B%20segoe%20ui%26amp%3Bquot%3B%2Ctahoma%2Carial%2C%26amp%3Bquot%3Bhelvetica%20neue%26amp%3Bquot%3B%2Chelvetica%2Csans-serif%3B%20font-size%3A%2014px%3B%20font-style%3A%20normal%3B%20font-variant%3A%20normal%3B%20font-weight%3A%20400%3B%20letter-spacing%3A%20normal%3B%20orphans%3A%202%3B%20text-align%3A%20left%3B%20text-decoration%3A%20none%3B%20text-indent%3A%200px%3B%20text-transform%3A%20none%3B%20-webkit-text-stroke-width%3A%200px%3B%20white-space%3A%20normal%3B%20word-spacing%3A%200px%3B%20margin%3A%200px%200px%2010px%200px%3B%22%3ETo%20summarize%2C%20if%20you%20are%20getting%20a%20503%20Service%20Unavailable%20that%20looks%20like%20the%20one%20in%20this%20blog%20post%2C%20and%20you%20have%20checked%20all%20of%20the%20items%20in%20the%20checklist.%20It%20is%20probably%20time%20to%20look%20at%20the%20URL%20Reservations%2C%20and%20make%20sure%20their%20are%20not%20any%20all%20inclusive%20registrations%20for%20the%20port%20the%20web%20site%20is%20running%20on.%20Meaning%20http%3A%2F%2F%2B%3A80%2F%2C%20a%20registration%20for%20http%3A%2F%2F%2B%3A80%2FApplication_Name%20is%20OK%2C%20as%20it%20only%20registers%20the%20Application_Name%20namespace%2C%20not%20the%20entire%20port%2080%20namespace.%3C%2FP%3E%0A%3CP%20style%3D%22box-sizing%3A%20border-box%3B%20color%3A%20%23333333%3B%20font-family%3A%20%26amp%3Bquot%3B%20segoe%20ui%26amp%3Bquot%3B%2Ctahoma%2Carial%2C%26amp%3Bquot%3Bhelvetica%20neue%26amp%3Bquot%3B%2Chelvetica%2Csans-serif%3B%20font-size%3A%2014px%3B%20font-style%3A%20normal%3B%20font-variant%3A%20normal%3B%20font-weight%3A%20400%3B%20letter-spacing%3A%20normal%3B%20orphans%3A%202%3B%20text-align%3A%20left%3B%20text-decoration%3A%20none%3B%20text-indent%3A%200px%3B%20text-transform%3A%20none%3B%20-webkit-text-stroke-width%3A%200px%3B%20white-space%3A%20normal%3B%20word-spacing%3A%200px%3B%20margin%3A%200px%200px%2010px%200px%3B%22%3E%3CSTRONG%3EAuthor%3A%20bretb%3C%2FSTRONG%3E%3C%2FP%3E%0A%3C%2FLI-WRAPPER%3E%3CP%3E%3C%2FP%3E%0A%3CP%3E%26nbsp%3B%3C%2FP%3E%3C%2FLINGO-BODY%3E

Symptoms

 

So a co-worker of mine was setting up IIS 7.0 on a new Windows 7 machine, and when they were browsing to http://localhost they were getting a 503 Service Unavailable error as shown here:

 

503 Service Unavailable

 

Troubleshooting

 

This seemed pretty trivial so I went through the following checklist.



  • Is W3SVC started?      Yes


  • Is the Default Web Site started?   Yes

  • Is the Application Pool Disabled?  No

  • Is the Application Pool Started?   Yes

  • Is the w3wp.exe process for the application running?  No

  • Are their any WAS or W3SVC Events in the Application or System Event logs?  No

  • Are their any entries in the IIS Log for the web site?  No

    1. Are their any entries in the HTTP error logs?   Yes

      2010-02-17 17:28:47 ::1%0 49991 ::1%0 80 HTTP/1.1 GET / 503 - N/A -


    So what could be going on here? After a bit of troubleshooting I was able to find a event in the event log that led me in the correct direction. Here is a summary of the event:


    Log Name:      System
    Source:        Microsoft-Windows-HttpEvent
    Date:          2/17/2010 9:26:44 AM
    Event ID:      15007
    Task Category: None
    Level:         Information
    Keywords:      Classic
    User:          N/A
    Computer:      computer.domain.com
    Description:
    Reservation for namespace identified by URL prefix http://+:80/ was successfully added.
    Event Xml:
    <Event xmlns=http://schemas.microsoft.com/win/2004/08/events/event">
      <System>
        <Provider Name="Microsoft-Windows-HttpEvent" Guid="{7b6bc78c-898b-4170-bbf8-1a469ea43fc5}" EventSourceName="HTTP" />
        <EventID Qualifiers="16384">15007</EventID>
        <Version>0</Version>
        <Level>4</Level>
        <Task>0</Task>
        <Opcode>0</Opcode>
        <Keywords>0x80000000000000</Keywords>
        <TimeCreated SystemTime="2010-02-17T17:26:44.064479100Z" />
        <EventRecordID>42570</EventRecordID>
        <Correlation />
        <Execution ProcessID="4" ThreadID="44" />
        <Channel>System</Channel>
        <Computer>computer.domain.com</Computer>
        <Security />
      </System>
      <EventData>
        <Data Name="DeviceObject">\Device\Http\ReqQueue</Data>
        <Data Name="Url">http://+:80/</Data>
      </EventData>
    </Event>


    The key part of this event is that it mentions the namespace http://+:80/ was successfully added. What exactly does this mean? I am not going to go into detail in this blog, but this blog explains why URL reservations are typically used.  In our case we first need to list all of the registered URLs via the following command, run from an Administrative command prompt.


    netsh http show urlacl

    Reserved URL            : http://+:80/
            User: NT SERVICE\Machine
                Listen: Yes
                Delegate: No
                SDDL: D:(A;;GX;;;S-1-5-21-2127521184-1604012920-1887927527-67210)


    Root Cause & Solution


    We can see that the URL is reserved. The "+" sign means any host header, and the :80 means anything on port 80. Since there is no application path after the final "/" it reserves anything that runs on port 80. This is what is causing the 503 Service Unavailable errors, as this reservation will prevent W3SVC from obtaining the rights to listen on port 80 when it tries to start the site. Furthermore, applications that run in IIS do not need explicit reservations to run, only non-IIS applications have to reserve a URL namespace if they want to use HTTP to listen for requests.  One example are WCF applications that are running on HTTP, as these are non-IIS applications that use HTTP to listen for requests.   To resolve the problem for the default web site, we have to remove the reserved namespace for port 80 with the following command.


    netsh http delete urlacl http://+:80/

    URL reservation successfully deleted


    After removing this namespace, WCF applications or other non-IIS applications running on this server may break.  So a new URL reservation may be needed for those applications.  The new URL reservation should point to the specific application on port 80, not the root.  This will prevent the URL reservation from blocking all applications under port 80.  The next question is who added the namespace in the first place?  There is no real way to identify that, however the HTTPEvent 15007 in the System Event log will give a good indication of the Date and Time the reservation was made.


    Conclusions


    To summarize, if you are getting a 503 Service Unavailable that looks like the one in this blog post, and you have checked all of the items in the checklist. It is probably time to look at the URL Reservations, and make sure their are not any all inclusive registrations for the port the web site is running on. Meaning http://+:80/, a registration for http://+:80/Application_Name is OK, as it only registers the Application_Name namespace, not the entire port 80 namespace.

    Author: bretb