Exchange 2013 - "Mail sent to the wrong Office365 region. ATTR35"

Question

Exchange 2013 - "Mail sent to the wrong Office365 region. ATTR35"

36584367 201

Hi. We have Exchange 2013 and all of a sudden we cannot reach SOME recipients that use Office365. On our Exchange we are getting an error saying "Mail sent to the wrong Office365 region. ATTR35". Any idea what this could be please? Thanks

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Answer 1

Andy David - MVP 158K MVP Volunteer Moderator

Interesting that each of these have multiple mx records and both have issues. I don't think this is your problem, I think its on them to fix.

In both examples they have mx records that are not valid any longer.

basmalta-com.mail.eo.outlook.com is wrong and not supported anymore, it should be set to the correct mx record for their domain in 365. ( the eo. part)

in the second example, the mx record with a preference of 10 is invalid. Its possible your server is attempting to send to that secondary MX record.

can you contact them and let them know? :)

otherwise, this is not on you to fix.. you can point them to: https://learn.microsoft.com/en-us/exchange/troubleshoot/email-delivery/wrong-office-365-region-exo

36584367 201 Reputation points

2021-04-21T12:13:16.25+00:00

Hi Andy,

Thanks a lot for this! Will let them know :)
36584367 201 Reputation points

2021-04-21T12:20:29.733+00:00

Hi Andy,

How come then they are able to receive mails from other companies? I can also reach them via my Gmail or Hotmail accounts.
36584367 201 Reputation points

2021-04-21T12:56:46.157+00:00

Andy I can confirm the problem was from recipient side! Thanks a million

Answer 2

Andy David - MVP 158K MVP Volunteer Moderator

See:

https://learn.microsoft.com/en-us/exchange/troubleshoot/email-delivery/wrong-office-365-region-exo

Answer 3

36584367 201

Hi AndyDavid,

Yes I saw this post already but did not manage to follow. I opened a ticket with Microsoft and they are seeing to this. Thanks

Andy David - MVP 158K Reputation points MVP Volunteer Moderator

2021-04-16T11:43:56.303+00:00

So you are not sending messages via a smarthost to 365 from Exchange?
36584367 201 Reputation points

2021-04-16T11:47:23.6+00:00

No I am not that's why its strange this happened
Andy David - MVP 158K Reputation points MVP Volunteer Moderator

2021-04-16T12:01:03.65+00:00

The other option would be if the recipient has their mx record set incorrectly.

https://mxtoolbox.com could tell you that

or....its an issue on the 365 side :)

Answer 4

Lucas Liu-MSFT 6,191

Hi @MatthewVassallo-0389 ,
All these users in the same Office 365 tenant?
Did you send the email directly without going through any equipment from Exchange?
Dis you change any Exchange settings before this issue occurred?

If possible, please share the complete NDR information with us.Please note that covering your personal information.
As Andy said, please check if the recipient’s MX record is correct.
Please try to send an email to these user mailboxes from other mailboxes.

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36584367 201 Reputation points

2021-04-19T06:39:38.783+00:00
Hi,

Thanks for your reply. Hereunder are the results

NDR attached

The recipients mailbox is hosted with Office365 cloud so I assume their MX record is correct

The recipients are receiving mail from other mailboxes from other companies. When we tried sending with our hotmail or gmail accounts, mail was delivered.
Andy David - MVP 158K Reputation points MVP Volunteer Moderator

2021-04-19T11:38:13.077+00:00

Thats not the same NDR you described above though is it?
That indicates you have a fireall issue or something blocking outbound mail.

Did this work before and if so, when did it change?
36584367 201 Reputation points

2021-04-19T11:42:15.587+00:00

The error I posted is the one showing on Exchange directly. This is from my Outlook :). The one of Exchange gives a better indication
Lucas Liu-MSFT 6,191 Reputation points

2021-04-21T07:09:48.557+00:00

Hi @36584367 ，
Can the user mailboxes send mail to other external recipients?
Is the generation server is your Exchange server?
Dis you change any Exchange settings recently?

According to the error code message: "550 4.4.7" and "441 4.4.1".
1.Plesae check whether open all network ports required for Exchange on firewall.And no firewall rules will affect Exchange communication.
Please refer to: Network ports for clients and mail flow in Exchange 2013

2.If possible, please make sure that the SPF record set by the other party's domain contains your domain, and your server IP has not been added to the blacklist by the other party by mistake. In addition, also make sure that your DNS record settings are also correct.
Lucas Liu-MSFT 6,191 Reputation points

2021-04-21T07:10:46.393+00:00

3.Please check the Queue viewer in the Exchange Toolbox to check if there are any unsuccessful send emails in it. If so, please check if there are additional error messages in the last error.
In addition, there is an article about error code 550 4.4.7, although it is about Exchange online, you can refer to it: Fix email delivery issues for error code 550 4.4.7 in Exchange Online

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36584367 201 Reputation points

2021-04-21T08:10:49.99+00:00

Hi,

Yes we do have queues of mails which cannot be sent. Strangely enough only 2 domains are unreachable from our end. I am attaching an NDR from Exchange side. Thanks!
Lucas Liu-MSFT 6,191 Reputation points

2021-04-21T09:41:15.84+00:00

Hi @36584367 ，
I noticed that your personal information appears in the screenshot you provided. In order to protect your personal information, I overwrite the information and upload it again.
For the information you provide, I will update after I research on it.
Andy David - MVP 158K Reputation points MVP Volunteer Moderator

2021-04-21T11:21:33.333+00:00

For those two domains you have issues sending to, what are their mx records?

mxtoolbox.com
36584367 201 Reputation points

2021-04-21T11:25:45.367+00:00

Hi Andy,

Yes till now only those two. Hope we don't get anymore. I am attaching mxtoolbox results. Thanks

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Exchange 2013 - "Mail sent to the wrong Office365 region. ATTR35"

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