Hello all, sometimes I find in forum that people complain about Error 404.3 – Not Found. I decided to write the post about this issue and hope it will solve your problem.

Hmm… I assume that you have installed Windows Server 2012. When you upload your files, try to browse your site, you see this error:

One of the issues might be :

It complaints about missing handler mappings for the created web site. this is obvious when you look at it closely as follows

Go to the Desired web application listed under "Default web site" under IIS 8 and open "handler mappings"

Here most of the handler mappings are not listed. As a remedy to this click "Revert to Parent" and you will see the all handler mappings are inherited from the parent node.

This might solve the 404.3 error that you get