Google Activation Guide Postini Email Security - Manual (Page 36)

40 Activation Guide
I’m unable to change my MX records with my domain provider. Why am I
having trouble?
Most ISPs and domain name providers that host the email for your domain are
compatible with the message security service. However, 1and1 and XO
Communications are known providers that are currently not compatible with the
message security service. The message security service is not compatible with
providers that don't release mail server information, or don't allow you to change
the MX records with their hosted email service.
When you are finished switching your MX records to the message
security service, go to “Test Your MX Records” on page 41.