I received the following message when I tried to send an email to some external email accounts.
Your message did not reach some or all of the intended recipients.
Subject: FW: Vote for Darius
Sent: 5/28/2009 7:54 AM
The following recipient(s) cannot be reached:
firstname.lastname@example.org on 5/28/2009 7:57 AM
The message cannot be delivered due to a configuration error on the server. Please contact your Administrator.
<mail.checkpnt.com #5.3.0 smtp;553 5.3.0 <email@example.com>... Addressee unknown, relay=[184.108.40.206]>