User can send but not receive emails

Hello!
So I’ve just set up a band new server from scratch and am having trouble getting the email service to work 100%.
My dns is all correct, forward and reverse. The output of a changeip -checkhostname command is perfect. My domain name and its public ip address both point to each other fine and my A, MX and CNAME records have all been set at the domain vendor to point to my particular server.

I’ve made one user in WGM and that user can send emails no problem. But when I try to send an email back (or reply to the original message), this is the error I receive in the bounce message:

: Host or domain name not found. Name service error
for name=server.jinniferules.com type=A: Host not found
Reporting-MTA: dns; server.example.com
X-Postfix-Queue-ID: 75E7A223CE8
X-Postfix-Sender: rfc822; me@example.com
Arrival-Date: Wed, 12 Jan 2011 11:15:20 -0700 (MST)

Final-Recipient: rfc822; jinnifer@jinniferules.com
Original-Recipient: rfc822;jinnifer@jinniferules.com
Action: failed
Status: 5.4.4
Diagnostic-Code: X-Postfix; Host or domain name not found. Name service error
for name=server.jinniferules.com type=A: Host not found

Any thoughts on this?

Thanks!