Creating a CNAME record for any of the domain addresses or subdomains you have within a hosting account will enable you to direct it to a different domain/subdomain. The forwarded domain address will lose all its records - A, MX and so on, and will take the records of the domain it is being pointed to. In this light, you simply can't create a CNAME record to forward your domain name to a third-party provider and maintain a working e-mail service with the first hosting company. It is also essential to know that a CNAME record is always a string of words and not a number as it is frequently mistaken for the A record of the domain being redirected. One of the primary uses of a CNAME record is to point a domain that you own through one company to the servers of some other company if you have set up a website with the latter. By doing this, the website will appear under your own domain, not under some subdomain provided by the third-party provider.