Dear all,
 
I would very much appreciate if anyone could help me identify the problem
with several valid email addresses on my Listserv. Every time an email gets
sent out, several addresses return an error stating: "The enclosed message,
found in the --- mailbox and shown under the spool ID 6106 in the  system
log, has been identified as  a possible delivery error notice for  the
following  reason: "X-Report-Type:" field  found in  the mail header." An
attached message reads, "This is a delivery status notification,
automatically generated by MTA mailgateway1.slu.edu on Thu, 11 Aug 2005
20:29:32 -0500 Regarding recipient(s) : [log in to unmask] Delivery status :
Failed. Message could not be delivered to the domain - slu.edu. Failed to
accept the recipients. MTA Response :550."
 
I am told that this address and others are correct (including a few at AOL),
so I wonder what the header might be contributing to having it rejected, and
how I might change it. Thanks so much in advance.
 
Josh