I'm having a problem with IIS not loading a dotnet core 2.1 web app.

Theres no errors anywhere I can find (event viewer).  The response from the server is just

This site can’t be reached

mysite refused to connect.

This is from chrome, edge, firefox similar error (there version of this).  Its not a 500 error from the server, just no response from the server.  It takes a while to get this, 30 seconds or so.  All other sites in IIS work, just my dotnet core 2.1 does not.

• Ive installed visual c++ 2015 version 3.
• Ive installed dotnet-hosting-2.1.3-win.
• Ive given "Everyone" permission to the app folder and all subfolders
• Ive rebooted my machine
• I've restarted IIS
• Ive created the directory "logs".
• Ive set stdoutLogEnabled="true" to see if I could get an error message.
• Ive configured the appool to be "no managed code".
• Ive set the app pool to run as an administrator user.
• Ive set permissions on the application directory to everyone recursively.
• Ive checked under sites[mysite]\modules to ensure "AspNetCoreModule" is listed there and it is.
• Ive tried this on 2 machines (windows 10 and windows server 2016)
• Ive built this app on two different machines (to see if that was the issue, however ever unlikely).

I'm completely out of ideas.  The standard check of running the app from dotnet "mysite.dll" is what you would usually do to debug this, but the fact that starts and works fine on port 5000, means its definitely an issue with IIS not loading something.  I just have no clue as to what.

Ive basically followed every step from here 

https://neelbhatt.com/2018/01/30/deploy-net-core-application-to-iis-step-by-step-guide/

And nothing....