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

Recently i faced this issue.

After performing the below actions , this issue got resolved

Solution:

Check #1: Make sure IIS installed correctly  else install the IIS Server extensions  etc.. as specified below

• Click on next and install 
• Restart the IIS

This will fix your issues.