WCF : The page you are requesting cannot be served because of the extension configuration

This is for WCF on Windows Server 2012.

Trying to access a svc URL and get:

"The page you are requesting cannot be served because of the extension configuration. If the page is a script, add a handler. If the file should be downloaded, add a MIME map."


The solution is:

Server Manager --> Add roles and features --> Features --> .NET Framework 4.5 Features --> WCF Services --> enable HTTP Activation.

Enjoy!