some emails not being delivered to our Inboxes

Question

some emails not being delivered to our Inboxes

Julia Palova 0

Hello Support Team,

I have an issue with receiving emails. Two emails, sent on November 5 and November 10, did not arrive in either my inbox or my colleague's inbox.

The sender informed me that the emails keep bouncing and are not reaching our inboxes.

However, other emails from the same sender, including a meeting invitation received today, are being delivered successfully.

Could you please investigate why these two specific emails were not delivered and advise where the issue might be?

Thank you for your help!

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Answer 1

Hi Julia Palova,

Thank you for reaching out and for sharing the details

Since the affected messages were sent on specific dates and are being rejected while other emails from the same sender are being delivered successfully, this suggests the issue may be related to those individual messages rather than a general mail flow problem.

I recommend contacting your organization's IT administrator and asking them to perform a Message Trace in the Microsoft Exchange Admin Center for the two missing emails (November 5 and November 10). The Message Trace results can help determine:

Whether the emails reached your Microsoft 365 tenant.
If the messages were rejected, quarantined, filtered, or redirected.
Whether a mail flow rule, anti-spam policy, anti-phishing policy, or transport rule blocked the messages.
The exact bounce or non-delivery reason returned to the sender.

When contacting your IT administrator, please provide:

The sender's email address.
The recipient email addresses (yours and your colleague's).
The approximate date and time the emails were sent.
Any Non-Delivery Report (NDR) or bounce-back message that the sender received.

The bounce-back message is particularly important, as it often contains the specific error code and reason for the delivery failure.

If the Message Trace confirms that the emails never reached your organization's Microsoft 365 environment, the sender may need to review their mail server logs or email security solution to determine why the messages were rejected before delivery.

For more information, your IT admin may refer to: Message trace in the new EAC in Exchange Online | Microsoft Learn

In case you do not know who is your IT admin, kindly refer to this article: How do I find my Microsoft 365 admin? - Microsoft Support

I hope the information I shared earlier was somewhat helpful in addressing your issue. If you have any further questions or updates, please don’t hesitate to share. I’m always happy to assist further if needed.