Fix domain forwarding DNS Mail box issue

Hi I have a site a [login to view URL] which is hosted at amazon. We run plesk and centos To configure it to work i had to change the dns zone as below [login to view URL] CNAME [login to view URL] Then the domain [login to view URL] without the www. didnt work. So i was advised to set up a webredirection so typing, [login to view URL] and [login to view URL] in a browser URL would load the same webpage. The problem i have now is mail to the [login to view URL] domain will not work. I need someone who understands domain name forwarding and DNS to help me fix these issues. thanks