Setting up a CNAME record for any of the domains or subdomains you've got in a hosting account will allow you to point it to a different domain/subdomain. The forwarded domain will lose all of its records - A, MX etc, and will take the records of the domain it's being pointed to. In this light, you simply can't create a CNAME record to point your domain name to a third-party provider and keep a functional email service with the first hosting company. It is also essential to know that a CNAME record is always a string of words rather than a number because it is generally confused with the A record of the Internet domain being redirected. One of the major uses of a CNAME record is to direct a domain address you own through one provider to the servers of some other company in case you have set up a website 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.