ASP.NET Core hosting environment variable ignored

Question

I have two web sites on my staging server, and both are ASP.NET Core sites that run in IIS. I have set the environment variable ASPNETCORE_ENVIRONMENT to

Answer 1

As said in this similar question, the trick was simply to set the app pool to load the user variables (IIS -> Server -> App Pools -> Right click on pool -> Set application pool defaults... -> Load User Profile = True).

I configured only one of my app pools accordingly, thus only one of the sites could access the environment variables.