Subject: Mail System Error - Returned Mail

From: "The Post Office" <[email-masked]>
Date: Thu, 7 Jul 2005 13:33:01 +0200

The original message was received at Thu, 7 Jul 2005 13:33:01 +0200 from ietf.org [79.64.189.50]

----- The following addresses had permanent fatal errors -----
<[email-masked]>

----- Transcript of session follows -----
... while talking to ietf.org.:
>>> MAIL From:"The Post Office" <[email-masked]>
<<< 507 User unknown