question

Darwish-8567 avatar image
0 Votes"
Darwish-8567 asked ZhengqiLou-MSFT commented

Exchange Online - Users not getting email but works if sent to Distribution List

Hi,

We have an issue where an email is not being received by the users if sent directly but is received if it's sent to the distribution list they belong to.

I have tried the following but to no avail:

  • Created a mailflow so that the emails are bypassed from the Spam Filter

  • Created a new spam filter policy and added the sender's domains as well IP to the allowed list

  • Created a new phishing policy and added the sender's domains as well IP to the allowed list

  • Checked Quarantine but is not there

The weird thing is when I run Message trace, the email is not showing on the results but is showing if if it's sent to the Distribution List.

I'm a bit stumped as to why it's not working if sent directly to the user but works if it's sent to a distribution list.

Any help is appreciated.

Thanks

office-exchange-server-mailflow
5 |1600 characters needed characters left characters exceeded

Up to 10 attachments (including images) can be used with a maximum of 3.0 MiB each and 30.0 MiB total.

ManuPhilip avatar image
0 Votes"
ManuPhilip answered ManuPhilip commented

Check, if the email size is not over than than allowed limit. Also, see if there are some hidden inbox rule for the user

 Get-InboxRule -mailbox user@yourdomain.com | fl name,description,enabled 


· 6
5 |1600 characters needed characters left characters exceeded

Up to 10 attachments (including images) can be used with a maximum of 3.0 MiB each and 30.0 MiB total.

Thanks for your reply, I have checked for the email size and it is not that big and it is within the acceptable size limit. There are also no hidden inbox rule for the user/users.

I have run a message trace and it's not showing in the report.

If it's getting blocked or quarantined, it should still show up in message trace no?

0 Votes 0 ·

Yes, message trace also displays the message as quarantined.
\Another thought on the issue is, check if the mail is being delivered to a different mail client like a phone application where it is moved to the quarantine folder there as per the rule there

0 Votes 0 ·

I've checked that as well but it's the same.

Weirdly, the user receives the email if it's sent to a Distribution list the user is a member of.

I'm baffled as to why that works but doesn't if it's sent directly to the user's email address.

is there another way to view email delivery logs other than message trace?

0 Votes 0 ·
Show more comments
ZhengqiLou-MSFT avatar image
0 Votes"
ZhengqiLou-MSFT answered ZhengqiLou-MSFT commented

Hi @Darwish-8567 ,

Are the sender and recipients all in Exchange online?
And did you receive any NDRs after sending the message to another user?

Please try to create a new Exchange online account and test sending messages to the other users.
Also see if you could send to this new account with the other users.

I'm not sure if the migration has any mistakes, so you could check it first.

Best regards,
Lou


If the response is helpful, please click "Accept Answer" and upvote it.
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

· 3
5 |1600 characters needed characters left characters exceeded

Up to 10 attachments (including images) can be used with a maximum of 3.0 MiB each and 30.0 MiB total.

Hi @Darwish-8567 ,

Do the suggestions above help? If the issue has been resolved, please click “Accept as answer” to mark the helpful reply as an answer, this will make answer searching in the forum easier and be beneficial to other community members as well.

If you are still stuck in this issue, please feel free to post your questions.

Regards,
Lou


If the response is helpful, please click "Accept Answer" and upvote it.
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

0 Votes 0 ·

Hi @ZhengqiLou-MSFT ,

Thank you for your reply. The senders are external but the recipients are all Exchange Online.

No NDR's were received, nothing on message trace and nothing on Quarantine either.

It tried doing a test email to an On-Premise mailbox and it works.

Migration wise, the mailboxes are newly created and not migrated.

Kind Regards,
Darwish

0 Votes 0 ·

Hi @Darwish-8567 ,

Thank you for sharing the details. But there are something still not clear.

You're using a hybrid Exchange right? Is the mail flow set to on-prem or online? And is the distribution list on-prem?
Also please check if there are any Transport rules set to delete the message.

Best regards,
Lou

0 Votes 0 ·