Subject: Returned mail: see transcript for details

From: Mail Delivery Subsystem <[email-masked]>
Date: Wed, 24 Sep 2008 09:48:25 -0500

The original message was received at Wed, 24 Sep 2008 09:48:24 -0500
from inet.kirov.net [213.222.51.114]

   ----- The following addresses had permanent fatal errors -----
<[email-masked]>
    (reason: 550 5.1.2 <[email-masked]>... Invalid Rcpt - Sender is <[email-masked]>)

   ----- Transcript of session follows -----
... while talking to localhost:
>>> DATA
<<< 550 5.1.2 <[email-masked]>... Invalid Rcpt - Sender is <[email-masked]>
550 5.1.1 <[email-masked]>... User unknown
<<< 503 Need RCPT (recipient)