How get update to meeting to go to current membership of distribution list?

Margaret Auld-Louie 41 Reputation points

If someone sends a meeting update to a distribution list, should that update be going to the current members of the list or will it go to the people that were members at the time the meeting was created? I keep getting support tickets complaining that some new members of a managers distribution list are not receiving all emails to the list. In the latest ticket, they complain that a list member didn't get emails about changes/updates to a meeting. When I did a message trace, I see 3 emails in one day about the meeting sent to the list. 2 of the emails are updates to the meeting and they did not get to that list member. The 3rd email is a cancellation notice and that email did get to that list member. I don't know when the user was added to the list as I haven't been able to find a ticket requesting that. What is the expected behavior of these meeting update emails? Should they be getting to all current list members? If they are not, is there anything I can do to fix this? People are opening tickets with IT (me) complaining about not getting all the emails to the managers list and saying "fix this". The previous ticket I had on this (which was about emails to the managers list not getting to someone, not related to a meeting invite), I opened a ticket with Microsoft but could not reproduce the issue so got nowhere. So I am not sure what to do about this.

Our environment is Active Directory on premises with distribution groups, syncing to Office 365. We use Exchange Online. We do not have any Exchange servers on premises.

Microsoft Exchange Online Management
Microsoft Exchange Online Management
Microsoft Exchange Online: A Microsoft email and calendaring hosted service.Management: The act or process of organizing, handling, directing or controlling something.
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  1. Vasil Michev 95,081 Reputation points MVP

    It should go to the current membership, and it seems to be confirmed by the message trace results. Just to clarify, is this a "traditional" DL or a "modern" Office 365 Group? For the latter, each member need to be "subscribed" in order to receive updates directly in their mailbox, and while calendar subscription is toggled on by default, you should probably double-check on this for the affected users.
    I'd also suggest redoing the message trace but with the actual user's addresses as the recipient, you might be able to obtain some additional details as to what happened to said messages.

  2. KyleXu-MSFT 26,206 Reputation points

    @Margaret Auld-Louie

    Here is a summary about this question, you could have a check whether it is correct:

    1. Group AD account created on local AD. Then synchronize to Exchange online and used in Exchange online.
    2. Updated meeting requests will not be sent to updated group members.

    First, if the problem cannot be reproduced, this will not be hard to troubleshoot. I test it in my lab, emails could be sent to new members when update meeting.

    I guess this phenomenon may be caused by cache, if this phenomenon occurs again, you could delete this group from the "To" list, then re-enter the email address manually. Check whether email could be sent to all users now.

    You can also try to resend email from OWA in this same way.

    Personally, I would suggest you recreate a new distribution group from Exchange online directly. Because it could reduce time for group membership updates and easier to manage group from Exchange online.

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