HTTP Error 502.3 - Bad Gateway There was a connection error while trying to route the request.

Greetings,

I am having issues with running or debugging my .Net Core 2.1 app on IIS. I was able to run a test Core application on IIS after following some examples and instructions, but when I deployed my real application, I keep getting 

HTTP Error 502.3 - Bad Gateway

There was a connection error while trying to route the request.

Yet I have not been able to obtain any more information as to the cause of the issue. Event logs don't offer any real detail and I haven't been able to produce any other types of logs.

Thanks.