Need help with Exchange #550 5.7.1 Recipient not authorized error

FreeRangers used Ask the Experts™
Yesterday I upgraded Exchange 2007 SP1 to SP3 and later that day a user was expecting an email but the email never came through. It seem that the sender got this bounce back message:

Subject: Undeliverable: *message subject*
mail.*my domain*.ca rejected your message to the following e-mail addresses:
*user in my domain* *user's email address*)
mail.*my domain*.ca gave this error:
Recipient not authorized, your IP has been found on a block list
Your message wasn't delivered due to a permission or security issue. It may have been rejected by a moderator, the address may only accept e-mail from certain senders, or another restriction may be preventing delivery.

Diagnostic information for administrators:
Generating server: *sender's server*
*recipient's email address*
mail.*my domain*.ca #550 5.7.1 Recipient not authorized, your IP has been found on a block list ##
Original message headers:
Received: from *sender's server* by
*sender's server* with mapi; Mon, 18 Oct 2010
 17:18:22 -0600
From: *sender*
Subject: *subject*
Thread-Topic: *subject*
Thread-Index: ActZvtzv8iLctLt+Slaki3TmcFt/BQ==
Date: Mon, 18 Oct 2010 23:18:20 +0000
Message-ID: <*message id*>
References: <*references*>
Accept-Language: en-US
Content-Language: en-US
Content-Type: multipart/alternative;
MIME-Version: 1.0

I know my domain isn't on any block lists, and the sender was from our provincial government, so I'm very certain they aren't on a block list. My question is could this have anything to do with the upgrade from SP1 to SP3 or is it just a coincidence that on the day I upgrade our exchange service pack a user can't receive an email because of a supposed block list?  No other users have complained to me about not getting or being able to send email.
Watch Question

Do more with

Expert Office
EXPERT OFFICE® is a registered trademark of EXPERTS EXCHANGE®
Are you not receiving from a particular domain to a specific user?
what happens if the sender send an email to someone else in your domain.
Please check your ip block list or sender block list in the HUB server:
Go to "Organization Configuration" and select your HUB server, check if you have "Anti-spam" TAB

most probably it is not the reason SP3 upgrade. Don't matter who is sending you an email, you can't be sure that it is not blacklisted, so it is always good to check blacklists you are using on your server. But I can't say that this is the case.
Can you check your agent log for detailed info about the reason of rejecting?
Log is located in \Exchange Server\TransportRoles\Logs\AgentLog folder.
More info:


I looked in the log and the sender was blocked by Spamhaus, I then checked anti spam tab on the HUB server and sure enough Exchange was using the Spamhaus database. What's weird is  the senders domain doesn't show up when I do a search on Spamhaus' website.
Exploring SQL Server 2016: Fundamentals

Learn the fundamentals of Microsoft SQL Server, a relational database management system that stores and retrieves data when requested by other software applications.

On black lists are normally listed IP addresses, so they can be sending from different IP address or maybe they are using smart host to send their mail and that smart host is blacklisted. For some black lists also can take some time to propagate to all servers that some IP address is not blacklisted anymore.


yeah, that was my thought too,  that they are using a different ip address, as I'm sure the provincial government has more than one ip. Either way it looks like the problem is not with my exchange server.
It seems like it is not. Spamhaus is one of most reliable RLBs.
At logs it is logged also senders IP address (Agent log or receiving SMTP log) - you can use it to check the spamhaus database again - but there are six different blask lists at spamhaus.
You can whitelist their IP address, but you can end with lots of spam so it is better that they take care of reason why they were blacklisted in first place.


Thanks.  I've already let the sender know and his IT are going to look into it.

Do more with

Expert Office
Submit tech questions to Ask the Experts™ at any time to receive solutions, advice, and new ideas from leading industry professionals.

Start 7-Day Free Trial