Web Hosting Talk : Web Hosting Main Forums : Hosting Security and Technology : Error on valid emails "The following address(es) failed"

[Apocalypse]

Hello, im having this error on a cpanel box:

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:

  validuser@myrealdomainnamehere.com
    All deliveries are handled by MailScanner

------ This is a copy of the message, including all the headers. ------
Return-path: <validuser@myserver.domainhere.net>
Received: from validuser by myserver.domainhere.net with local-bsmtp (Exim 4.34)
id 1BSM8S-0006go-4l
for validuser@myrealdomainnamehere.com; Mon, 24 May 2004 16:33:25 -0400
Received: from [63.126.72.183] (helo=prodmx01.prod.appriss.com)
by myserver.domainhere.net with esmtp (Exim 4.34)
id 1BSM5p-0006aw-3q
for validuser@myrealdomainnamehere.com; Mon, 24 May 2004 16:30:41 -0400
Received: from prodmx01 (prodmx01.prod.appriss.com [10.10.100.166])
by prodmx01.prod.appriss.com (Appriss SMTP Services) with ESMTP id D542F9D5
for <validuser@myrealdomainnamehere.com>; Mon, 24 May 2004 16:30:43 -0400 (EDT)
Message-ID: <26890858.1085430643871.JavaMail.notify@globalnotifications.com>
Date: Mon, 24 May 2004 16:30:43 -0400 (EDT)
From: "aa@domainofsenderhere.com" <aa@domainofsenderhere.com>
To: <validuser@myrealdomainnamehere.com>
Subject: American Airlines Flight Status Update
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline
Content-ID: 41791915@prodmx01
X-MailScanner-Information: Please contact the ISP for more information
X-MailScanner: Found to be clean
X-MailScanner-SpamCheck: 
X-MailScanner-From: aa@domainofsenderhere.com
X-Spam-Exim: uR1fj7suvvy1TqEIpYlV_vHA
X-Spam-Status: No, hits=0.0 required=6.2 tests=none autolearn=no version=2.63
X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on 
myserver.domainhere.net
X-Spam-Level:

Any idea what might be causing this? this doesnt happen always, but happens to almost all email accounts on random intervals, most of the email gets thru just fine.

Im using RH 9.0 updated kernel

exim, mailscanner, clamav, spamassassin

Thanks in advance,

Apocalypse

[Apocalypse]

Anyone else has this problem?
or have any clues what might be wrong in my config?

TIA