Subject: Mail delivery failed: returning message to sender

From: Mail Delivery System <[email-masked]>
Date: Fri, 22 Aug 2008 04:47:27 +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. ------

From: =?koi8-r?B?6MHSydTPzg==?= <[email-masked]>
To: <[email-masked]>
Subject: =?koi8-r?B?9d7Fws7ZyiDL1dLTOiAi8sHa0sHCz9TLwSDGyc7BztPP18/KIMTPyw==?=
	=?koi8-r?B?1c3FztTBw8nJICjCydrOxdMt0MzBzs/XLCD0/O8pIg==?=
Date: Fri, 22 Aug 2008 03:47:24 +0200