When publishing an ASP.NET Core web application to Azure, some users may encounter this error:

“Error 500.0 — ANCM In-Process Handler Load Failure”

If you have an application that runs locally but fires this error when published to Azure, here are steps that should resolve this issue:

1. If your application does not include a web.config file, add the following web.config file to the solution:

In the process of building an IIS web app today, I got stuck for 20 minutes while trying to add a Web Form .aspx file. Turns out you need to an extra .NET Framework template that isn’t installed by default in newer versions of Visual Studio.

To resolve this issue:

1. Go to the VisualStudioSetup.exe and select “Modify.”

2. Under “Web and Cloud”, select ASP.NET and Web development.

3. Under Installation Details > Azure Development > Optional, select .NET Framework project and item templates.