Temporary Local Problem 451 and Rejected E-mail

Update: Apparently all caused by the server name listed as sending, that domain name not resolving.

That domain name is sort of represented as example.net in the dumps below.

Getting identical messages, in one e-mail, regarding two totally separate servers...

<

blockquote>
This is the mail system at host mail.democraticmedia.ca.

me@example.com (expanded from socialway@example.com): host example.com[72.25.144.102] said: 451 Temporary local problem - please try later (in reply to RCPT TO command)

other@example.org (expanded from socialway@example.com): host mail.example.org[76.212.67.42] said: 451 Temporary local problem - please try later (in reply to RCPT TO command)

451 Temporary local problem - please try later (in reply to RCPT TO command

Answers from: http://www.directadmin.com/forum/showthread.php?t=9152

The hostname of my machine is serv2.developerhosting.nl and the nameservers are:
ns1.developerhosting.nl and ns2.developerhosting.nl. i've added the domain developerhosting.nl but i had to add two A records for the nameservers.

You sure did :).

The "local problem" was that the sending server couldn't find your DNS servers.

error 451 = You have no sender adres set in squirrel @ options
Thanks! This turns out to be the true source of my problem. It is impossible to send mail using Squirrelmail until a return address has been set in the Options->Personal Information section of Squirrelmail.

Full dump of diagnostic information sent in the error e-mail:

Reporting-MTA: dns; mail.democraticmedia.ca
X-Postfix-Queue-ID: 063549448E2
X-Postfix-Sender: rfc822; message@example.net
Arrival-Date: Mon, 30 Jun 2008 23:34:38 -0500 (CDT)

Final-Recipient: rfc822; benjamin@example.com
Original-Recipient: rfc822;socialway@example
Action: failed
Status: 4.0.0
Remote-MTA: dns; example.com
Diagnostic-Code: smtp; 451 Temporary local problem - please try later

Final-Recipient: rfc822; steve@example.org
Original-Recipient: rfc822;socialway@example.com
Action: failed
Status: 4.0.0
Remote-MTA: dns; mail.example.org
Diagnostic-Code: smtp; 451 Temporary local problem - please try later

Received: from mta1.tavant.com (unknown [67.151.---.143])
by mail.democraticmedia.ca (Postfix) with ESMTP id 063549448E2
for ; Mon, 30 Jun 2008 23:34:38 -0500 (CDT)
Received: from socialwayapp02.tavant.com ([192.168.33.51])
by mta1.tavant.com (8.13.1/8.13.1) with ESMTP id m614EnRm008821;
Mon, 30 Jun 2008 21:14:52 -0700
Received: from socialwayapp01.tavant.com (unknown [193.168.---.50])
by socialwayapp02.tavant.com (Postfix) with ESMTP id 388042C050;
Mon, 30 Jun 2008 21:28:11 -0700 (PDT)
Message-ID: <9690924.01214886705200.JavaMail.root@socialwayapp01.tavant.com>
From: TeamRoadmap
To: roadmap@_____.com, socialway@example.com
Subject: SocialWay Reports DailyAnalysis_6_30
MIME-Version: 1.0
Content-Type: multipart/mixed;
boundary="----=_Part_0_29945686.1214886705133"
MyHeaderName: myHeaderValue
Date: Mon, 30 Jun 2008 21:28:11 -0700 (PDT)

Resolution