My company is using email domaing - abc.com; whenever we tried to send mails to xxx.com, we get the error message:
Delivery has failed to these recipients or distribution lists:
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.
The following organization rejected your message: mb-exc2007.abc.com
Sent by Microsoft Exchange Server 2007
Diagnostic information for administrators:
Generating server: ca-exc2007.abc.com
mb-exc2007.abc.com #550 5.7.1 Unable to relay ##
Original message headers:
Received: from mb-exc2007.abc.com (192.168.9.97) by ca-exc2007.abc.com
(192.168.9.96) with Microsoft SMTP Server (TLS) id 184.108.40.206; Mon, 5 Dec 2011
Received: from ca-exc2007.abc.com ([192.168.9.96]) by mb-exc2007.abc.com
([192.168.9.97]) with mapi; Mon, 5 Dec 2011 16:36:11 +0800
From: "ME (email@example.com)"
To: "firstname.lastname@example.org'" <email@example.com>
Date: Mon, 5 Dec 2011 16:36:07 +0800
Subject: testing 3...
Thread-Topic: testing 3...
Originally, there are 2 exchange 2007 servers - ca-exc2007 and mb-exc2007. Few weeks ago, MB-exc2007 was down, so all exchange roles have been transferred to CA-exc2007.