Returned mail: DNS server responded with 3 (Domain Not Found)

[Mail Delivery Subsystem <MAILER-DAEMON@xxxxxxxxxxx>]

The original message was received at Tue, 15 Jan 2008 00:03:13 +0200

  ----- The following addresses had permanent fatal errors -----
<720@xxxxxxx>

  ----- Transcript of session follows -----
... while issuing MX query to 91.151.81.1
554 DNS server responded with 3 (Domain Not Found)

Reporting-MTA: DNS; mail.turccomhost.com
Arrival-Date: Tue, 15 Jan 2008 00:03:14 +0200

Original-Recipient: RFC822; <720@phx.gbl>
Final-Recipient: RFC822; <720@phx.gbl>
Action: failed
Last-Attempt-Date: Tue, 15 Jan 2008 00:03:13 +0200

--- Begin Message ---

To:	720@xxxxxxx
Subject:	Online banka şifresini çalan virüse dikkat
From:	"Dikkat !" <info-inventor@xxxxxxxxxxx>
Date:	Tue, 15 Jan 2008 00:03:13 +0200

--- End Message ---