I doubt that anyone could help with any troubleshooting, without knowing the exact configuration you have in your setup. This is the best place to start looking – something needs to be set properly….but what it is will have to be determined at your end. It might help if you had any error messages or something from your Event Logs to share, but with this general “it doesn’t work” posting, there is no way to help. Here is a link to Microsoft information, and Here is even more on Exchange. Best of luck.