[Nevinovatu] {Spam? 0.00} Mail delivery failed: returning message to sender

[Mail Delivery System]

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:

  litijus7 at paeurope.com
    SMTP error from remote mail server after RCPT TO:<litijus7 at paeurope.com>:
    host avscan-beta.viatel.net [194.42.224.171]:
    550-Callout verification failed:
    550 550 5.1.1 User unknown