HTTP Error 404.3 – not Found

Error:
HTTP Error 404.3 – not Found
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.

Resolution
1. Start the command window (cmd) as an Administrator.
2. Navigate to:
C:\windows\Microsoft.Net\Framework\v3.0\Windows Communication Foundation\

In case you are running on a 64Bit machine, than navigate to: C:\windows\Microsoft.Net\Framework64\v3.0\Windows Communication Foundation\
3. Run the following command: ServiceModelReg –i

Enjoy!