Subject: Returned mail: see transcript for details

From: Mail Delivery Subsystem <[email-masked]>
Date: Wed, 24 Sep 2008 07:52:14 +0400

The original message was received at Wed, 24 Sep 2008 07:52:14 +0400
from root@localhost

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

   ----- Transcript of session follows -----
550 5.1.1 [email-masked]... User unknown