Subject: Returned mail: see transcript for details

From: Mail Delivery Subsystem <[email-masked]>
Date: Thu, 4 Sep 2008 09:02:11 +0400 (MSD)

The original message was received at Thu, 4 Sep 2008 09:02:10 +0400 (MSD)
from ala234.internetdsl.tpnet.pl [83.17.30.234]

   ----- 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 main.iwan.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)