Visual Studio : Unable to connect to web server IIS Express

This is with VS 2017.

I was looking at a .NET Core project and wanted to change from http to https.

So under Properties / Debug, I checked the "Enable SSL" checkbox.

This changes the port so I then did a copy / replace of the old port to the new one and changed the URL to https e.g.

http://localhost:5000 became https://localhost:44326

Then I got "Unable to connect to web server IIS Express".

Consulted with Mr. Google.

The solution that worked for me was to:

• Close the VS project
• In File Explorer, navigate to the project and delete the entire ".vs" folder
• Restart the project
• Run as "Debug"
• Works

Apparently, it has something to do with the "applicationhost.config" file.

 Enjoy!