Troubleshooting HTTP 502.5 startup issues in Azure AppService for ASP.NET Core Websites

Whenever ASP.NET Core website fails to start in Azure AppService we get HTTP
502.5 error and this below error page

1. 
   Go to SCM site, just add .scm before .azurewebsites.net in
   the URL as shown below
   

   
   
   
   
   

   
   


2. In the SCM website, click on the Debug Console | CMD
   


3. Click on Site | WwwRoot folder
   


4. Look for web.config file, now click on the pencil icon to edit it
   


5. Change the web.config as highlighted below
   

   
   
   
   
   

   
   

   
   
   
   
   
   
   

   <aspNetCore processPath="dotnet" arguments=".\webapp.dll" stdoutLogEnabled="true" stdoutLogFile="\\?\%home%\LogFiles\stdout"> </aspNetCore>

   
   


6. Now, try to browse to the home page of your website
   


7. You should see same startup failure error message
   


8. Go back to SCM website
   


9. Navigate to d:\home\Logfiles
   


10. You should now see stdout_xxx_datetime.log as shown below
    

    
    
    
    
    



11. Click on the pencil icon to view it.
    


12. You should see the callstack and line # of the exception
    as shown below