Visual Studio Remote Debugger Firewall Error
This is a relatively common problem (in my experience).
Generally, ensuring that port 4022 for Visual Studio 2019 or 4020 if you’re using 2017 isn’t block by your network resolves the issue.
However in my case, this didn’t work.
The Web App in question had a custom domain, on the DNS side it was a CNAME since being a sub-domain
Finding the IP address of the app (via Properties in Azure) and making two entries in host file on windows for the CNAME and original *.azurewebsites.net sub domain fixed the issue.