Setting up a CNAME record for any one of the domains or subdomains you have in a hosting account will permit you to direct it to a different domain/subdomain. The forwarded domain address will lose all of its records - A, MX and so forth, and will take the records of the domain name it's being redirected to. In this light, you simply can't set up a CNAME record to redirect your domain to a third-party provider and maintain a functional e-mail service with the first hosting provider. Additionally, it is essential to know that a CNAME record is always a string of words rather than a number as it's frequently wrongly identified as the A record of the Internet domain being redirected. One of the major uses of a CNAME record is to point a domain name you own through one provider to the servers of some other company assuming you have created a site with the latter. By doing this, the Internet site will appear under your own domain name, not under some subdomain provided by the third-party company.