Asp.Net Core – HTTP Error 500.0 – ANCM In-Process Handler Load Failure

I spent a few hours trying to fix this problem today.  What I thought was strange was that one web site loaded and worked fine, and another web site, on the same server using the exact same files did not work.

Our fix turned out to be somewhat simple.  You can only have one Asp.Net Core module running in process per IIS App Pool.  We have long been sharing an app pool with several web sites.  I guess as we migrate to Asp.Net Core running on IIS, that we will need to create a separate App Pool for each site.

I figured this out by reviewing the Event Viewer Application logs.

“Only one inprocess application is allowed per IIS application pool. Please assign the application ‘/LM/W3SVC/1/ROOT/Nightly/SQL2012/LucityDocumentServerCore’ to a different IIS application pool.”

Eventi ID 1008

 

• HTTP Error 500.0 – ANCM In-Process Handler Load Failure
• The specified version of Microsoft.NetCore.App or Microsoft.AspNetCore.App was not found.
• The in process request handler, Microsoft.AspNetCore.Server.IIS, was not referenced in the application.
• ANCM could not find dotnet.
• failed to start application iis aspnetcore module v2 0x80004005