Can't debug on Visual Studio 2017 with local IIS - Unknown Error 0x80004005

Question

I'm working on a ASP.NET MVC project which was developed under IIS express and haven't had any problems with it ever since. However, when I try to run the debugger with local IIS, debugger doesn't attach and throws an error pop up stating - "Unable to start debugging on the web server. Operation is not supported. Unknown Error 0x80004005".

Actual error popup

Web settings in VS project

Event log doesn't show anything regarding this error, as well as Visual studio in log mode. If I create a new project on VS 2017 and try debugging it on local IIS - it works without a problem.

I'm using standard IIS site, in which:

• Application pool uses administrator account
• Port: 44311
• IIS express SSL certificate

Already tried:

• Making sure that IIS settings are correct.
• Deleting VS cache, repairing VS, pulling clean source code from repository.

I was struggling with this error whole day, so any related information will be very appreciated.

Answer 1

In your project settings, open the "Web" tab and make sure you are debugging the app using the HTTPS address.

Project -> Properties -> Web -> Project Url

I am using HTTPS and a redirect and got exactly this error. Although there are other causes, I'm guessing it is the HTTPS one that is affecting you.