Exciting new technologies come with exciting new ways to frustrate developers :D
Working with ASP NET Core you may have come across this message a few times and wondered what the heck is the problem?
You look in the even viewer and you none the wiser, as the error is just as vague as this page you have seen.
The solutions is to actually add some extra settings on the BuildWebHost builder in Startup.cs
Obviously all of this information is provided in the official documentation - But who reads that? :D