This morning a SharePoint developer contacted us to report that his site is not working in one of our higher environments.
The error that we are getting is saying that aspnetcore module v2 is not present. We compared the web server features on both servers but they were the same.
Next, we looked for modules in IIS and found that this environment where the site is not working is missing the v2 module.
Further investigation led to the dll available in Windows/IIS/ directory.
Next, we used cmd and AppCmd to install the v2 module using the Path of the dll. However, that broke some other sites on the Server. Finally, we had to remove and uninstall the manually installed module version 2.
Update: During our next DR Dry Run, we got the same issue affecting another site. This time we created a Ticket to Microsoft. They have responded and we are going to setup a call with our Team.
Solution Suggested: Disable shared configuration, install ASPNetCoreModuleV2 and re-enable the Shared Config.