received a call informing me of 554 bounce backs. See below:
This is a delivery status notification, automatically generated by MTA domain1.com on Wed, 05 Jun 2013 09:21:05 -0400 Regarding recipient(s) : firstname.lastname@example.org Delivery status : Failed. Message could not be delivered to domain <domain2.com> .554; Denied
[p02c11m066.mxlogic.net] (Mode: normal) MTA Response :554
Called out to the email admin that was reporting the bounce backs and we both completed a Telnet to Port 25 to Test SMTP Communication to each others email server with success, but they still getting '554 denied'.