IIS Express Visual Studio - Cannot debug localhost

Been trying to resolve this issue for a few days now. I've done a ton of searching and tried several solutions - nothing has helped thus far.

I have a Visual Studio 2017 project. It has been running and debugging fine for years now. Suddenly, the other day I can no longer debug the application. Regardless of what browser I select (IE, Edge, Chrome, Firefox, etc) - the same error message is generated:


Also, it takes forever for VS to open the browser to show this message. Additionally, if I start without debugging (ctrl + F5), the site works and loads as expected.

Things I've tried thus far:

  • Deleting everything from the IIS Express folder in My Documents
  • Re-installing IIS Express
  • Repairing IIS
  • Changing the port number in the project
  • Various IIS Express reset commands
  • Resetting IE settings
  • Clearing caches

There are probably a few others too, but at this point I feel I've exhausted all my options.

Anyone else encounter this and if so how did you fix it?