Subject: Undeliverable mail: Заявку на обучение по подтверждаем

From: <[email-masked]>
Date: Fri, 24 Oct 2008 00:34:02 +0400

Failed to deliver to '<[email-masked]>'
SMTP module(domain dep2.city-xxi.ru) reports:
 host dep2.city-xxi.ru says:
 550 [email-masked] unknown user account