Subject: Returned mail: see transcript for details

From: Mail Delivery Subsystem <[email-masked]>
Date: Mon, 11 Aug 2008 16:02:14 +0300 (EEST)

The original message was received at Mon, 11 Aug 2008 16:02:13 +0300 (EEST)
from net-93-150-18-3.t2.dsl.vodafone.it [93.150.18.3]

   ----- The following addresses had permanent fatal errors -----
<[email-masked]>
    (reason: 550 [email-masked]... No such user)

   ----- Transcript of session follows -----
... while talking to credoclmail.credo.kiev.ua.:
>>> DATA
<<< 550 [email-masked]... No such user
550 5.1.1 <[email-masked]>... User unknown
<<< 503 Issue RCPT TO: command before DATA command