migrated .net core 2.2 app to 3.1 and it won't serve up in Azure

Question

I have everything working locally, I have updated my build/deploy pipeline in Azure Dev Ops and everything builds and deploys fine however, when I call the site on my app service I get this error:

I have tried to find on the app service configuration page the place to change the .net core version (found this resource: https://www.hanselman.com/blog/UpdatingAnASPNETCore22WebSiteToNETCore31LTS.aspx) but I don't see any place to change the version - just the stack type. See 2nd screenshot:

Where do I need to go to update this to version 3.1? All other searches I"ve tried are coming up empty.

Answer 1

Confirm that the ASP.NET Core Extensions are installed. If the extensions aren't installed, install them manually:

1.In the DEVELOPMENT TOOLS blade section, select the Extensions blade.
2.The ASP.NET Core Extensions should appear in the list.
3.If the extensions aren't installed, select the Add button.
4.Choose the ASP.NET Core Extensions from the list.
5.Select OK to accept the legal terms. 6.Select OK on the Add extension blade. 7.An informational pop-up message indicates when the extensions are successfully installed.

After install ASP.NET Core 3.1(x64) Runtime Extension, then you will load your webapp successfully. Refer to this article to migrate from 2.2 to 3.1.