Using our backup mail service is very simple. However, if you are not
using our DNS, backup mail requires an extra step.
You'll need to configure an MX record for our backup mail server as a
secondary MX record.
First, go into the Backup MX Cont...
Each backup mail "slot" that you purchase is good for one domain at any given time. You can always change the domain that this slot is configured for (it may take the mail server up to 2 hours to update).
So, even if you are hosting multiple domains on...