when IIS acts like it can't see a .svc endpoint for a WCF web service

...you will see an error like so:

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.

 
 

...if you visit the .svc endpoint in a browser. This happened to me at Windows Server 2012 R2 in specific and I beat the problem by:

1. click on the Server Manager icon at the taskbar, probably the leftmost icon at the taskbar after that pseudostart menu thing that Microsoft added back in to the Metro interface
2. at the "Dashboard" click on "Add roles and features"
3. click next through the "Add Roles and Features Wizard" until you are at "Features"
4. under ".NET Framework 4.5 Features" you'll find "WCF Services" and under that you'll want to check the checkbox for "HTTP Activation"
5. finish up

 
 

Here are some things I found along the way:

• http://stackoverflow.com/questions/11460142/cannot-serve-wcf-services-in-iis-on-windows-8
• http://garvis.ca/2013/01/04/installing-netfx3-on-windows-server-2012/