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Exchange Online - NDR not getting sent to user RRS feed

  • Question

  • I did a test of a large file size to an external domain from GMail and got an NDR from GGmail within 10 mins that it was too large for the recipient server. When I sent from an O365 mailbox, the NDR never gets to me. Does anyone know what might be causing that? I thought NDR was hands off so surely there's not some configuration somewhere in EXO I have to worry about..?

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    Thursday, July 23, 2020 2:49 PM

All replies

  • Check message tracking for that NDR not the over sized message
    Thursday, July 23, 2020 3:19 PM
  • Check message tracking for that NDR not the over sized message

    I’m not sure how to check because I don’t see any email going to the original sender from any address after the failure
    Thursday, July 23, 2020 3:42 PM
  • Check message tracking for that NDR not the over sized message


    I’m not sure how to check because I don’t see any email going to the original sender from any address after the failure

    Look for messages from MicrosoftExchange329e71ec88ae4615bbc36ab6ce41109e@yourdefaultdomain.com

    Sent to the original 365 mailbox sender.

    Thursday, July 23, 2020 4:10 PM
  • Check message tracking for that NDR not the over sized message


    I’m not sure how to check because I don’t see any email going to the original sender from any address after the failure

    Look for messages from MicrosoftExchange329e71ec88ae4615bbc36ab6ce41109e@yourdefaultdomain.com

    Sent to the original 365 mailbox sender.


    Ok it looks like we not don’t get it when we send it to a mailbox that has a mail flow rule set to add the external domain to BCC. It successful delivers to the mailbox in our tenant, but the BCC address (external domain) added Exchange trace reports failed to deliver to due size exceeding, but an NDR never gets sent nor shows as in any message trace of its own. If we send the same email directly to that external domain, then we do get the NDR and do indeed see that Microsoft sender address In message trace. But no where do we see it for the failed emails that were done via Mail flow rule BCc.
    Thursday, July 23, 2020 4:45 PM
  • Check message tracking for that NDR not the over sized message


    I’m not sure how to check because I don’t see any email going to the original sender from any address after the failure

    Look for messages from MicrosoftExchange329e71ec88ae4615bbc36ab6ce41109e@yourdefaultdomain.com

    Sent to the original 365 mailbox sender.


    Ok it looks like we not don’t get it when we send it to a mailbox that has a mail flow rule set to add the external domain to BCC. It successful delivers to the mailbox in our tenant, but the BCC address (external domain) added Exchange trace reports failed to deliver to due size exceeding, but an NDR never gets sent nor shows as in any message trace of its own. If we send the same email directly to that external domain, then we do get the NDR and do indeed see that Microsoft sender address In message trace. But no where do we see it for the failed emails that were done via Mail flow rule BCc.
    that makes sense if you think about it. The sender is not the one BCC the message, Exchange is.
    Thursday, July 23, 2020 5:10 PM
  • That’s what is confusing though because the sender, say Susan@ourdomain.com is the sender, and the BCC failure due to email size in the trace says that Susan@ourdomain.com will be receiving an NDR regarding the failure.
    Thursday, July 23, 2020 5:24 PM
  • That’s what is confusing though because the sender, say Susan@ourdomain.com is the sender, and the BCC failure due to email size in the trace says that Susan@ourdomain.com will be receiving an NDR regarding the failure.

    Yea, true. But Im wondering if that is the side-effect of using a rule to do that. 

    I'd have to test that out, but that seems like what its doing.

     

    Thursday, July 23, 2020 5:28 PM
  • Hi,

    I did some tests in my test environment, and found the same phenomenon. When the Bcc message is blocked, no NDR will be generated to the sender.

    I created two mail flow rules to Bcc and reject specific messages with NDR message. Here is my test result.

    1) Message 1 sends to gmail account and block it. NDR is generated and sent to sender successfully.

    2) Message 2 sends to user02 inside my organization. Bcc to gmail account and block it. NDR is not generated.

    3) Message 3 sends to user02 and block it. NDR is generated and sent to sender successfully.

    4) Message 4 sends to gmail account. Bcc to user02 and block it. NDR is not generated.

    My test results show that, when Bcc message is blocked (No matter Bcc recipient is internal or external user) no NDR message is generate to the sender. 

    However, if I Bcc manually when send messages instead of using mail flow rule, the NDR message is generated successfully.

    This Microsoft Online: Exchange Online Forum will be migrating to a new home on Microsoft Q&A, please refer to this sticky post for more details.

    Regards,

    Lydia Zhou


    Microsoft Online: Exchange Online will be migrating to a new home on Microsoft Q&A! We invite you to post new questions in the new forum.

    For more information, please refer to the sticky post.

    Friday, July 24, 2020 6:29 AM
  • Hi,

    I did some tests in my test environment, and found the same phenomenon. When the Bcc message is blocked, no NDR will be generated to the sender.

    I created two mail flow rules to Bcc and reject specific messages with NDR message. Here is my test result.

    1) Message 1 sends to gmail account and block it. NDR is generated and sent to sender successfully.

    2) Message 2 sends to user02 inside my organization. Bcc to gmail account and block it. NDR is not generated.

    3) Message 3 sends to user02 and block it. NDR is generated and sent to sender successfully.

    4) Message 4 sends to gmail account. Bcc to user02 and block it. NDR is not generated.

    My test results show that, when Bcc message is blocked (No matter Bcc recipient is internal or external user) no NDR message is generate to the sender. 

    However, if I Bcc manually when send messages instead of using mail flow rule, the NDR message is generated successfully.

    This Microsoft Online: Exchange Online Forum will be migrating to a new home on Microsoft Q&A, please refer to this sticky post for more details.

    Regards,

    Lydia Zhou


    Microsoft Online: Exchange Online will be migrating to a new home on Microsoft Q&A! We invite you to post new questions in the new forum.

    For more information, please refer to the sticky post.


    Hi @Lydia, Cool stuff I appreciate you sharing results. What shall I do instead as a workaround? Possibly open a support case?
    Tuesday, July 28, 2020 3:47 AM
  • I would open a case yes. To at least get that hopefully documented as a known issue or possibly "fixed"
    Tuesday, July 28, 2020 12:02 PM
  • You can take Andy's suggestion into consideration, or go to O365 UserVoice to post the requirement for this case. For your reference: Office 365 Admin.

    This Microsoft Online: Exchange Online Forum will be migrating to a new home on Microsoft Q&A, please refer to this sticky post for more details.

    Regards,

    Lydia Zhou


    Microsoft Online: Exchange Online will be migrating to a new home on Microsoft Q&A! We invite you to post new questions in the new forum.

    For more information, please refer to the sticky post.

    Thursday, July 30, 2020 1:22 AM
  • [Note] This forum will be locked down, you can continue to post in here before 8/10/2020. It is highly recommended to register the Microsoft Q&A Platform and create new thread in Microsoft Q&A Platform to continue the discussion.

    Here is a brief summary about replies above. Hope it can help more people with similar issues.

    Issue Symptom:

    I did a test of a large file size to an external domain from GMail and got an NDR from GGmail within 10 mins that it was too large for the recipient server. When I sent from an O365 mailbox, the NDR never gets to me.

    It looks like we not don’t get it when we send it to a mailbox that has a mail flow rule set to add the external domain to BCC.

    Cause:

    This is by design. When the Bcc message is blocked, no NDR will be generated to the sender. However, if I Bcc manually when send messages instead of using mail flow rule, the NDR message is generated successfully.

    Suggestions:

    Contact the Microsoft support team for more details to know if it's a known issue or possibly "fixed". Or go to O365 UserVoice to post the requirement for this case.

    This Microsoft Online: Exchange Online Forum will be migrating to a new home on Microsoft Q&A, please refer to this sticky post for more details.

    Regards,

    Lydia Zhou


    Microsoft Online: Exchange Online will be migrating to a new home on Microsoft Q&A! We invite you to post new questions in the new forum.

    For more information, please refer to the sticky post.

    Tuesday, August 4, 2020 9:05 AM