Subject: Returned mail: see transcript for details

From: Mail Delivery Subsystem <[email-masked]>
Date: Fri, 24 Oct 2008 01:50:54 +0400

The original message was received at Fri, 24 Oct 2008 01:50:47 +0400
from 38.118.60.190.host.ifxnetworks.com [190.60.118.38]

   ----- The following addresses had permanent fatal errors -----
<[email-masked]>
    (reason: 550 5.1.1 <[email-masked]>... User unknown)

   ----- Transcript of session follows -----
... while talking to mail.sgp.gazprom.ru.:
>>> DATA
<<< 550 5.1.1 <[email-masked]>... User unknown
550 5.1.1 <[email-masked]>... User unknown
<<< 503 5.0.0 Need RCPT (recipient)