ASP.NET Core 2.1 Give me HTTP Error 502.5 - Process Failure

Question

After using deploying my .NET Core 2.1 App to my server, I get the following error when I access the page:

HTTP Error 502.5 - Process Failure

Following Microsoft's always helpful link on the same page (cough cough), I checked the Event View Log and it states:

Application 'MACHINE/WEBROOT/APPHOST/BLAH.COM' with physical root 'D:\inetpub\vhosts\BLAH.com\httpdocs\' failed to start process with commandline 'dotnet .\blah.dll', ErrorCode = '0x80070002 : 0.

The message was not only unhelpful, but completely irrelevant. I tried to enable the web app's logging in web.config:

<aspNetCore requestTimeout="23:00:00" processPath="dotnet" arguments=".\blah.dll" forwardWindowsAuthToken="false" stdoutLogEnabled="true" stdoutLogFile=".\logs\stdout" startupTimeLimit="3600" />

Oddly, no files were created in the Log directory until I granted permission to my IWPD process. The files it created weren't in the stdout directory as specified, but were in the parent log directory. They also were empty.

I ran the web app from the command line using:

dotnet .\blah.dll

The application appeared to run and I could see some messages on the screen, but I still got the same 502.2 error accessing the site with no additional information in the logs. I followed the troubleshooting steps for ASP.NET Core 2.1 and it mentioned this:

If the errors occur when making a request to the app, make a request to the host and port where Kestrel listens. Using the default host and post, make a request to http://localhost:5000/. If the app responds normally at the Kestrel endpoint address, the problem is more likely related to the reverse proxy configuration and less likely within the app.

I ran the web app from the command line and tried to access it using http://localhost:5000. I was finally able to access the site, but I still got the same 502.2 error via IIS.

It's obvious IIS and Kestrel are not communicating with each other. I don't understand why there's two web servers and how to get them to communicate with each other.

Answer 1

Solved the problem. The installer for the server's IIS module doesn't restart or warn the user to restart IIS. Restarting IIS loaded the necessary module. Clearly, this is a bug by any other name.