I have a subscriber who belongs to two lists on our server <tr.wou.edu>, a sub site of <wou.edu> Recently, I have been receiving the following error from both lists 11 08/10 08/21 [log in to unmask] Last error: 5.1.1 550 5.1.1 unknown or illegal user: user@s21699 The address in the subscriber lists for this person is <[log in to unmask]> If this weren't happening daily, I would assume it was just a spammer's spoofed address. Both lists are private. ------------ Regards, Randy Klumph [log in to unmask] The Teaching Research Institute Western Oregon University 345 N Monmouth Ave Monmouth, OR 97361 http://www.tr.wou.edu