Error sending email from a application to exchange online server

%3CLINGO-SUB%20id%3D%22lingo-sub-781218%22%20slang%3D%22en-US%22%3EError%20sending%20email%20from%20a%20application%20to%20exchange%20online%20server%3C%2FLINGO-SUB%3E%3CLINGO-BODY%20id%3D%22lingo-body-781218%22%20slang%3D%22en-US%22%3E%3CP%3EHI%2C%20I%C2%B4m%20getting%20this%20error%20when%20I%C2%B4m%20trying%20to%20send%20email%20from%20a%20application%20which%20is%20hosted%20on%20internal%20server%20to%20exchange%20online%20server%2C%20using%20mail.protection.outlook.com%3A%3C%2FP%3E%3CP%3E%26nbsp%3B%3C%2FP%3E%3CP%3EFailed%20to%20send%20e-mail%20notification%3A%20Error%20in%20processing.%20The%20server%20response%20was%3A%204.4.3%20Temporary%20server%20error.%20Please%20try%20again%20later%20ATTR3.1%20%5BVE1EUR01FT044.eop-EUR01.prod.protection.outlook.com%5D%3CBR%20%2F%3ESystem.Net.Mail.SmtpException%3A%20Error%20in%20processing.%20The%20server%20response%20was%3A%204.4.3%20Temporary%20server%20error.%20Please%20try%20again%20later%20ATTR3.1%20%5BVE1EUR01FT044.eop-EUR01.prod.protection.outlook.com%5D%3C%2FP%3E%3C%2FLINGO-BODY%3E%3CLINGO-LABS%20id%3D%22lingo-labs-781218%22%20slang%3D%22en-US%22%3E%3CLINGO-LABEL%3EExchange%3C%2FLINGO-LABEL%3E%3CLINGO-LABEL%3EOffice%20365%3C%2FLINGO-LABEL%3E%3C%2FLINGO-LABS%3E%3CLINGO-SUB%20id%3D%22lingo-sub-786053%22%20slang%3D%22en-US%22%3ERe%3A%20Error%20sending%20email%20from%20a%20application%20to%20exchange%20online%20server%3C%2FLINGO-SUB%3E%3CLINGO-BODY%20id%3D%22lingo-body-786053%22%20slang%3D%22en-US%22%3E%3CP%3E%3CA%20href%3D%22https%3A%2F%2Ftechcommunity.microsoft.com%2Ft5%2Fuser%2Fviewprofilepage%2Fuser-id%2F384883%22%20target%3D%22_blank%22%3E%40noi_1979%3C%2FA%3E%26nbsp%3B%20Have%20you%20checked%20other%20applications%20(on%20your%20on-premise)%20if%20they%20are%20able%20to%20relay%20the%20mails%20to%20O365.%20if%20not%20it%20is%20a%20Connector%20issue%20on%20your%20On-premise%20or%20some%20configuration%20change.%20But%20looking%20at%20the%20Error%20code%20%2C%20it%20looks%20like%20some%20temporary%20error.%20Can%20you%20remove%20the%20IP%20from%20the%20Connector%20%2C%20Run%20IISRESET%20from%20Exchange%20Server%2C%20Wait%20for%2010%20minutes.%20re-add%20the%20ip%20on%20your%20connector%20and%20Test%20again%20to%20see%20if%20it%20works%20%3F%3C%2FP%3E%3CP%3E%26nbsp%3B%3C%2FP%3E%3CP%3ECheers%3C%2FP%3E%3CP%3EAnkit%20Shukla%3C%2FP%3E%3CP%3E%26nbsp%3B%3C%2FP%3E%3C%2FLINGO-BODY%3E%3CLINGO-SUB%20id%3D%22lingo-sub-786065%22%20slang%3D%22en-US%22%3ERe%3A%20Error%20sending%20email%20from%20a%20application%20to%20exchange%20online%20server%3C%2FLINGO-SUB%3E%3CLINGO-BODY%20id%3D%22lingo-body-786065%22%20slang%3D%22en-US%22%3E%3CP%3E%3CA%20href%3D%22https%3A%2F%2Ftechcommunity.microsoft.com%2Ft5%2Fuser%2Fviewprofilepage%2Fuser-id%2F384883%22%20target%3D%22_blank%22%3E%40noi_1979%3C%2FA%3E%26nbsp%3B%3C%2FP%3E%3CP%3E%26nbsp%3B%3C%2FP%3E%3CP%3EAFAIk%20either%20your%20sending%20IP's%20are%20blocked%20at%20MS%20or%20may%20be%20your%20mails%20are%20getting%20throttled....%20would%20recommend%20to%20open%20a%20case%20with%20MS.%3C%2FP%3E%3CP%3E%26nbsp%3B%3C%2FP%3E%3CP%3EThanks%3C%2FP%3E%3CP%3E%26nbsp%3B%3C%2FP%3E%3CP%3ERobin%20Nishad%3C%2FP%3E%3C%2FLINGO-BODY%3E
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Occasional Visitor

HI, I´m getting this error when I´m trying to send email from a application which is hosted on internal server to exchange online server, using mail.protection.outlook.com:

 

Failed to send e-mail notification: Error in processing. The server response was: 4.4.3 Temporary server error. Please try again later ATTR3.1 [VE1EUR01FT044.eop-EUR01.prod.protection.outlook.com]
System.Net.Mail.SmtpException: Error in processing. The server response was: 4.4.3 Temporary server error. Please try again later ATTR3.1 [VE1EUR01FT044.eop-EUR01.prod.protection.outlook.com]

2 Replies
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@noi_1979  Have you checked other applications (on your on-premise) if they are able to relay the mails to O365. if not it is a Connector issue on your On-premise or some configuration change. But looking at the Error code , it looks like some temporary error. Can you remove the IP from the Connector , Run IISRESET from Exchange Server, Wait for 10 minutes. re-add the ip on your connector and Test again to see if it works ?

 

Cheers

Ankit Shukla

 

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@noi_1979 

 

AFAIk either your sending IP's are blocked at MS or may be your mails are getting throttled.... would recommend to open a case with MS.

 

Thanks

 

Robin Nishad