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
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
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://docs.microsoft.com/en-us/exchange/troubleshoot/email-delivery/wrong-office-365-region-exo
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.
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
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 :)
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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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.
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?
The error I posted is the one showing on Exchange directly. This is from my Outlook :). The one of Exchange gives a better indication
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