Undelivered Mail Returned to Sender

[Theo2k]

When trying sending an email to a user @noblecorp.com lots of times goes thru and other times I get the message below:

Reporting-MTA: dns; emsmta.messageone.com
X-Postfix-Queue-ID: 273214500689
X-Postfix-Sender: rfc822; user@domain.com
Arrival-Date: Fri, 19 Nov 2010 14:31:07 -0600 (CST)

Final-Recipient: rfc822; user@noblecorp.com
Original-Recipient: rfc822;user@noblecorp.com
Action: failed
Status: 4.4.1
Diagnostic-Code: X-Postfix; delivery temporarily suspended: connect to
66.60.244.25[66.60.244.25]: Connection timed out

______________________________________________________________

Here are the headers txt:

Received: from emsmta.messageone.com (localhost.localdomain [127.0.0.1])
by emsmta.messageone.com (Postfix) with ESMTP id 273214500689
for <user@noblecorp.com>; Fri, 19 Nov 2010 14:31:07 -0600 (CST)
Received: from localhost (chiemslo.messageone.com [10.101.5.7])
by emsmta.messageone.com (Postfix) with ESMTP id BCD014A402E
for <user@noblecorp.com>; Fri, 19 Nov 2010 14:31:06 -0600 (CST)
Received: from emsmta.messageone.com ([127.0.0.1])
by localhost (chiemsmtas1-04.chiems.messageone.com [127.0.0.1]) (amavisd-new, port 10025)
with ESMTP id 28633-33 for <user@noblecorp.com>;
Fri, 19 Nov 2010 14:31:06 -0600 (CST)
Received: from chiesmstr2-01.chies.messageone.com (dalesmta2-02.dales.messageone.com [10.180.196.218])
by emsmta.messageone.com (Postfix) with ESMTP id 5D37425C0D1
for <user@noblecorp.com>; Fri, 19 Nov 2010 14:31:00 -0600 (CST)
Received: from mymail.domain.com (mymail.domain.com [75.148.199.113] (may be forged))
by dalesmta2-02.dales.messageone.com (8.14.3/8.14.3) with ESMTP id oAJKQY9j016171
for <user@noblecorp.com>; Fri, 19 Nov 2010 14:26:35 -0600
Received: from HOUEXBE01.domain.int ([192.168.1.12]) by mymail.domain.com with Microsoft SMTPSVC(6.0.3790.4675);
Fri, 19 Nov 2010 14:26:10 -0600
Received: from 192.168.2.17 ([192.168.2.17]) by HOUEXBE01.domain.int ([192.168.1.12]) via Exchange Front-End Server mymail.domain.com ([192.168.1.21]) with Microsoft Exchange Server HTTP-DAV ;
Fri, 19 Nov 2010 20:26:04 +0000
User-Agent: Microsoft-Entourage/12.27.0.100910
Date: Fri, 19 Nov 2010 14:27:35 -0600
Subject: FW: Invoices
From: user <user@domain.com>
To: Dustin Stringer <user@noblecorp.com>
Message-ID: <C90C39DF.68EE%user@domain.com>
Thread-Topic: Invoices
Thread-Index: AcuFoH93bdUBVTT3QUKmnNAxAT16LwAuCh9AAAOproIABLnoKgBrfzzU
In-Reply-To: <5C5AC9E9AEB7254BBFAE5185D49659DC690435@HOUEXBE01.domain.int>
Mime-version: 1.0
Content-type: multipart/mixed;
boundary="B_3373021663_14167877"
X-OriginalArrivalTime: 19 Nov 2010 20:26:10.0198 (UTC) FILETIME=[00B2D360:01CB8828]
X-TM-AS-Product-Ver: SMEX-7.5.0.1166-6.5.1024-17778.001
X-TM-AS-Result: No--45.963400-5.000000-31
X-TM-AS-User-Approved-Sender: No
X-TM-AS-User-Blocked-Sender: No
X-MessageOne-Virus-Version: vendor=fsecure engine=2.50.10432:5.2.15,1.0.148,0.0.0000
definitions=2010-11-19_10:2010-11-19,2010-11-19,1970-01-01 signatures=0
X-MessageOne-Virus-Scanned: Clean
X-MessageOne-Envelope-Sender: user@domain.com
X-MessageOne-Spam-Details: rule=m657emszm_notspam policy=m657emszm score=0 spamscore=0 ipscore=0
suspectscore=3 phishscore=0 bulkscore=0 adultscore=0 classifier=spam
adjust=0 reason=mlx engine=5.0.0-1010190000 definitions=main-1011190170
X-MessageOne-Spam-Score: 0
X-MessageOne-Spam-Bar:
X-Virus-Scanned: by amavisd-new at emsmta.messageone.com


What does this mean?