On Thu, 23 Feb 2006 09:11:29 -0800, Buiskop19 wrote:

5.1.0 - Unknown address error 591-''

Could anyone please tell me what this error report means on a returned
email. Or maybe tell me where I can find out?
Many thanks.

Some mail systems (such as MS Exchange servers) are known for removing the
original error message in a reject, and creating their own version of a
message failure code. I expect that the whole return would have to be
posted before anybody could attempt to analyze the failure accurately. From
as little of the message as you have supplied, though, the meaning is in
these words of the message: "Unknown address". It is just that the
returning SMTP server may be lying about what it saw from the rejecting
SMTP server.

--
Norman
~Oh Lord, why have you come
~To Konnyu, with the Lion and the Drum