On 4 Dec 2006 at 10:03, [log in to unmask] wrote: >Lately I have been seeing the following error messages for several >subscribers on our ListServ. The emails do not seem to match up and I am > >Err First Last Address >--- ----- ----- ------- >1 11/29 11/29 [log in to unmask] Last error: smtp;550 5.7.1 Unable >to deliver to <[log in to unmask]> According to RFC1893: X.7.1 Delivery not authorized, message refused The sender is not authorized to send to the destination. This can be the result of per-host or per-recipient filtering. This memo does not discuss the merits of any such filtering, but provides a mechanism to report such. This is useful only as a permanent error.