Azure website message “You do not have permission to view this directory or page.”. What to do?

Question

After I published an ASP.NET Core app to Azure from Visual Studio 2017 I am getting this message when I click on the app url:

It was working fine before. Is

Answer 1

To turn errors on on production I had to set the ASPNETCORE_ENVIRONMENT environment variable to 'Development' which can be found in your app service here: