Subject: Returned mail: see transcript for details

From: Mail Delivery Subsystem <[email-masked]>
Date: Thu, 23 Oct 2008 09:28:11 +0700 (NOVST)

The original message was received at Thu, 23 Oct 2008 09:28:07 +0700 (NOVST)
from [220.68.231.167]

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

   ----- Transcript of session follows -----
... while talking to srv-mail.ntcom.loc.:
>>> DATA
<<< 550 5.1.1 User unknown
550 5.1.1 <[email-masked]>... User unknown
<<< 503 5.5.2 Need Rcpt command.