Creating a CNAME record for any one of the domains or subdomains that you've got in a hosting account will enable you to point it to a different domain/subdomain. The forwarded domain name will lose all of its records - A, MX and so on, and will take the records of the domain name it's being pointed to. In this light, you simply can't create a CNAME record to forward your domain name to a third-party company and maintain a working email service with the first hosting provider. Also, it is important to note that a CNAME record is always a string of words and never a number because it is often mistaken for the A record of the domain name being redirected. One of the major uses of a CNAME record is to point a domain address which you own through one provider to the servers of some other company if you have set up a website with the latter. By doing this, the Internet site will appear under your own domain address, not under some subdomain provided by the third-party company.