Unable to start debugging on the web server. Operation not supported. Unknown error. 0x80004005

I was trying to run my application hosted in IIS from Visual Studio. On pressing F5, it gave me the following error: "Unable to start debugging on the web server. Operation not supported. Unknown error. 0x80004005"

 

 

Go to the Application Pool in IIS by which your application is running. Right click -> Advanced Settings.  Enable 32-Bit Applications to True.