Code ignator 2.2.0 version working fine in Xampp. But failed to load in server

I think for us new users we always have this issue 404 page not found error especially while migrating from our local machine to the live server. The reason could be any one or all mentioned by mwhitney. I also had this issue and after a lot of checking and rechecking I found out that the problem was with the .htaccess file. Maybe you should check yours as well.