Help & FAQ - Apps
DNS: Why do you forward my site to www.domainname.com?
We automatically forward "domainname.com" to "www.domainname.com". This only applies to the root domain for services and sites that are set up with a CNAME record. It is not recommended to use a CNAME and MX record on a naked domain at the same time.
More information can be found at:
Why you shouldn't mix CNAME and MX records
Beware using CNAME and MX at the same time