Unable to start debugging on the web server. The remote server returned an error: (404) Not Found. Error when starting debug in Visual Studio

It appears that one of my colleagues has edited the web.config and added request filtering where he has removed the "DEBUG" verb. This disallowed debugging on F5. After adding it (or removing request filtering) everything works fine.

P.S. A lot of other possible problems with similar error is described here

In my case (Windows 10 & Visual Studio 2017) I had to install ASP.NET 3.5 and ASP.NET 4.7 under the Internet Information Services.

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