Delivery has failed to these recipients or distribution lists

we are getting Delivery has failed to these recipients or distribution lists
like this :

Delivery has failed to these recipients or distribution lists:

support@kw.zajil.com
Your message wasn't delivered because of security policies. Microsoft Exchange will not try to redeliver this message for you. Please provide the following diagnostic text to your system administrator.







Diagnostic information for administrators:

Generating server: zajil.com

support@kw.zajil.com
#< #5.7.1 smtp;550 5.7.1 RESOLVER.RST.AuthRequired; authentication required> #SMTP#

Original message headers:

Received: from mfw4.kems.net (168.187.5.206) by ZTMX01.zajil.com (10.0.1.11)
 with Microsoft SMTP Server id 8.1.336.0; Tue, 27 Oct 2009 13:56:51 +0300
X-IronPort-AV: E=Sophos;i="4.44,632,1249246800";
   d="bmp'146?jpg'146,145?scan'146,145,208,145,146,217";a="206084596"
Received: from mail.kems.net ([168.187.5.200])  by mfw3.kems.net with ESMTP;
 27 Oct 2009 14:04:28 +0300
Received: (qmail 3948 invoked by uid 89); 27 Oct 2009 14:04:27 +0300
Delivered-To: support@kems.net
Received: (qmail 3942 invoked from network); 27 Oct 2009 14:04:27 +0300
Received: from mfw4.kems.net (168.187.5.206)  by mail.kems.net with SMTP; 27
 Oct 2009 14:04:27 +0300
X-IronPort-AV: E=Sophos;i="4.44,632,1249246800";
   d="bmp'146?jpg'146,145?scan'146,145,208,145,146,217";a="206081891"
Received: from unknown (HELO edge-01.paci.kw) ([91.102.145.101])  by
 mfw3.kems.net with ESMTP; 27 Oct 2009 13:56:12 +0300
Received: from CASH-01.paci.kw (172.30.2.204) by edge-01.paci.kw
 (172.30.2.195) with Microsoft SMTP Server (TLS) id 8.1.340.0; Tue, 27 Oct
 2009 13:56:58 +0300
Received: from MBX-CLUSTER.paci.kw ([172.16.2.108]) by CASH-01.paci.kw
 ([172.16.2.107]) with mapi; Tue, 27 Oct 2009 13:55:15 +0300
From: Khaled Sallal <khaled@paci.gov.kw>
To: "support@kems.net" <support@kems.net>
CC: Joel Tamayo <tamayoj@paci.gov.kw>
Date: Tue, 27 Oct 2009 13:55:14 +0300
Subject: FW: PACI Matters
Thread-Topic: PACI Matters
Thread-Index: AcpW8OfDRyp6kQ+/RNq3H77f5P08wAAAvtew
Message-ID: <49C6D833C5020C4F95BE63488C31276BF9C3871FE3@MBX-CLUSTER.paci.kw>
Accept-Language: en-US
Content-Language: en-US
X-MS-Has-Attach: yes
X-MS-TNEF-Correlator:
acceptlanguage: en-US
Content-Type: multipart/mixed;
      boundary="_008_49C6D833C5020C4F95BE63488C31276BF9C3871FE3MBXCLUSTERpac_"
MIME-Version: 1.0
Return-Path: khaled@paci.gov.kw