Question : mail system has been rejected due to the sending MTA's poor reputation

Hi;
Can anyone explain what does it mean?  I went to the link http://www.senderbase.org/senderbase_queries/detailip?search_string=199.246.2.50, it said the sender reputation score is "poor"


Connected to 216.123.224.146 but greeting failed.
Remote host said: 554-mx12.exchange.telus.com
554-Connection Refused for your sending MTA of hostname: zeus.kos.net, IP Address of 199.246.2.50.
554-
554 Your access to this mail system has been rejected due to the sending MTA's poor reputation. You can confirm this at Please reference the following URL for more information: http://www.senderbase.org/senderbase_queries/detailip?search_string=199.246.2.50

--- Below this line is a copy of the message.

Return-Path:
Received: (qmail 29356 invoked by uid 89); 18 Aug 2009 17:17:00 -0000
Delivered-To: [email protected]
Received: (qmail 29342 invoked by uid 89); 18 Aug 2009 17:17:00 -0000
Cc: recipient list not shown: ;
Delivered-To: [email protected]
Received: (qmail 29307 invoked by uid 89); 18 Aug 2009 17:17:00 -0000
Received: from unknown (HELO mailgate2.kos.net) (199.246.2.15)
by zeus.kos.net with SMTP; 18 Aug 2009 17:17:00 -0000
X-ASG-Debug-ID: 1250615821-15e003200000-CsrbEO
X-Barracuda-URL: http://199.246.2.15:8000/cgi-bin/mark.cgi
Received: from p01c11o142.mxlogic.net (localhost [127.0.0.1])
by mailgate2.kos.net (Spam & Virus Firewall) with ESMTP
id 8EE55189548; Tue, 18 Aug 2009 13:17:01 -0400 (EDT)
Received: from p01c12.mxlogic.net (p01c12.mxlogic.net [1xx.x9.x8x.7x]) by mailgate2.kos.net with ESMTP id XwbajX4dNBlta39A; Tue, 18 Aug 2009 13:17:01 -0400 (EDT)
X-Ba

Answer : mail system has been rejected due to the sending MTA's poor reputation

Here is a link for more details

http://www.senderbase.org/help/sbrs

It basically means that the mail you are sending out from that domain is suspicious.  Either you have a virus sending mail or your mail looks like spam.