Issue: Distribution group not getting outside emails. Senders receive bounce messages:
Your message can’t be delivered because delivery to this address is restricted.
Generating server: BY2PR02MB106.namprd02.prod.outlook.com
Remote Server returned ‘550 5.7.1 RESOLVER.RST.AuthRequired; authentication required’
Solution: By default, distribution groups in Office 365 (and Exchange) will only receive email from internal senders.
In order to allow the distribution group to receive mail from outside the organization:
1) open Exchange Admin Center,
2) click recipients > groups
3) select (or create) the distribution group
4) click the edit button
5) click delivery management > select “Senders inside and outside of my organization”
6) click Save
This distribution group will now accept mail from outside senders.
The following steps will show you how to set all distribution groups or a subset of distribution groups to accept mail from senders outside the organization.
We are running Exchange 2010. I have a distribution group that I setup and when we email that address for that group, the external sender receives the rejection below. I have unchecked the box for "Require that all senders are authenticated" under message delivery restrictions. Internal users can send to the distribution group. I created a brand new distribution group with a different name and address and it can receive email from
external address fine. We do have a Spamtitan appliance that all mail goes through first but that shouldn't make a difference.
The error that the other server returned was:
550 5.1.1 <>: Recipient address rejected: undeliverable address: host mail.concept-pkg.com[192.168.1.1] said: 550 5.1.1 User unknown (in reply to RCPT TO command)
----- Original message -----
DKIM-Signature: v=1;
a=rsa-sha256; c=relaxed/relaxed;
d=gmail.com; s=20120113;
h=from:content-type:content-transfer-encoding:mime-version:subject
:message-id:date:to;
bh=fdkeB/A0FkbVP2k4J4pNPoeWH6vqBm9+b0C3OY87Cw8=;
b=IosMTnkVxSGp4aoOHAtUEDKyTvVGcJyhlSTrt/R8otWW68RDAXknerHj3LMHcQz5qM
u3/29/Q9H7700eF+hsxHETfWHWJlS3a6niH0f8G+GmkTr6rf2Li35zIM3jv07zt+S+py
FTYi4sAIAJsyFuyVhIvlNfiAnsDzcdA14ge4nKsck+0YvktaODdMJpwzOzf0D+uQN6R6
tpg8LBXknq2/+6fjjNBaJHTn0bcalEt1bjktrnz9Sh6tHny3LWvFp+CI5NsXAy4mCMSb
mb++j2AHiMfDmqFUlxx3rRGROM9bTOhtjDribMZy6MLllgip8vSIgNMg7y4BwPtTfgjV
urrg==
X-Received: by 10.236.30.70 with SMTP id j46mr1816848yha.73.1384189087879;
Mon, 11 Nov 2013 08:58:07 -0800 (PST)
Return-Path: <>
Received: from [192.168.2.120] (97-89-139-6.dhcp.gnvl.sc.charter.com. [97.89.139.6])
by mx.google.com with ESMTPSA id h66sm40355433yhb.7.2013.11.11.08.58.06
for <>
(version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128);
Mon, 11 Nov 2013 08:58:06 -0800 (PST)
From: xxxxxxxx
Content-Type: text/plain;
charset=us-ascii
Content-Transfer-Encoding: 7bit
Mime-Version: 1.0 (1.0)
Subject: Test
Message-Id: <>
Date: Mon, 11 Nov 2013 11:58:06 -0500
To:
X-Mailer: iPhone Mail (11B511)