Subject: Mail delivery failed: returning message to sender

From: Mail Delivery System <[email-masked]>
Date: Fri, 22 Aug 2008 04:43:44 +0300

This message was created automatically by mail delivery software.

A message that you sent could not be delivered to one or more of its
recipients. This is a permanent error. The following address(es) failed:

  [email-masked]
    SMTP error from remote mailer after RCPT TO:<[email-masked]>:
    host 10.1.100.10 [10.1.100.10]: 550 unknown user

------ This is a copy of the message's headers. ------

Date:	Fri, 22 Aug 2008 09:43:40 +0800
From:	=?koi8-r?B?78zYx8Eg98zBxMnNydLP187B?= 
	<[email-masked]>
Reply-To: [email-masked]
To: [email-masked]
Subject: =?koi8-r?B?8NLBy9TJ3sXTy8/FIMbJzsHO08/Xz8Ugzc/ExczJ0s/Xwc7JxQ==?=