Depending on where your email is hosted, the following articles may be helpful:
Unfortunately, EasyName is not compatible with our service as they are unable to accept mail when MX records are pointed externally. (ACS13177364)
If you are having trouble getting set up, and none of the above articles applies to your domain, then the General Workaround for Stubborn Hosts instructions may work for you.
If you have found a solution for a specific hosting provider, please share it with us so that we can update this page.