Anett wrote:

We seem to have a problem when one of our users recieve messages from
one specific remote sender. The messages are delivered all the way to
the back-end server, but there a NDR is created:

"A configuration error in the e-mail system caused the message to
bounce between two servers or to be forwarded between two recipients.
Contact your administrator."

This sounds like a message a sender would receive, not a recipient. It's
the result of two mail routers thinking that each is the forwarder for
itself; i.e., router A thinks that in order to reach the recipient, router B
must handle the message and router B thinks that A should handle the
message.

Who sent the original messge that elicited this NDR and who received the
NDR?
--
Brian Tillman