Creating a CNAME record for any of the domains or subdomains you have in a hosting account will enable you to redirect it to a different domain/subdomain. The forwarded domain address will lose all its records - A, MX etc, and will take the records of the domain name it's being directed to. In this light, you simply can't set up a CNAME record to forward your domain name to a third-party company and keep a functional e-mail service with the first provider. It is also essential to know that a CNAME record is always a string of words rather than a number as it is frequently wrongly identified as the A record of the domain address being forwarded. One of the main uses of a CNAME record is to direct a domain which you own through one company to the servers of another company when you have set up an Internet site with the latter. That way, the website will appear under your own domain name, not under some subdomain provided by the third-party provider.