> 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.

Analyzing such reports, to determine which elements appeared where, can be a
bit convoluted. This is not LISTSERV's fault, but a consequence of the
number of different, and differently hacked, servers out there.

From the description, it looks to me that the X-Report-Type: field is not in
the headers of the mail sent out via your list, but in the item that is sent
back by the recalcitrant gateway. If you are a subscriber to the list, you
should be able to check this in the headers of your own copies.

"Failed to accept the recipients" could easily be an erroneous description,
created by a programmer who didn't provide enough flexibility. This is quite
common with spam filters, so it could mean that your list is sending from a
domain that has been blacklisted for some (possibly idiotic) reason.

I have lists where unnecessarily losing subscribers is a Very Bad Idea, so I
generally wind up contacting the subscribers directly and maybe working with
their email people to get my domain whitelisted. (If I can't reach the
subscribers, it's an indication the addresses have really gone bad.) More
Draconian approaches (NOMAIL or simply deleting the problem subscriptions)
are possible, depending on the importance--at your end--of maintaining
contact with your subscribers.

Hal Keen