One user is not receiving incoming emails from a specific domain, while other users can.

Question

Subject: Email Issue for a Specific User

Hello,

We have a user in our tenant who is not receiving emails from a specific company with whom we do business. While this user can send emails to their contact at that company's domain, our user does not receive any incoming emails in return.

I can see the emails our employee sends to the company's domain in the logs, but I do not see any incoming emails from that domain for our specific user.

We have other users who can both send and receive emails with the partner company's domain, and I can see all their activity in the logs. This issue appears to be isolated to just this one user. The user's mailbox is set to allow all incoming emails and is not set to block anything.

We do not have any on-premises servers; we use Entra ID, Defender, and Exchange in the cloud. There are no mail flow rules configured in the Exchange Admin Center, except for an external mail warning. We are using the default Microsoft Defender Anti-Phishing and Anti-Spam policies.

If I can't find the incoming emails in our logs, does that mean they are not reaching our Exchange server?

Do you think this is an issue with our user's mailbox or are the incoming emails not reaching the mailbox?

Any help will be greatly appreciated,

Thank you.

Answer 1

Hello, @LM-5132,

Welcome to the Microsoft Q&A platform!

Based on your description, if the incoming emails are not appearing in your logs, it suggests that they might not be reaching your Exchange server at all. Here are a few steps and considerations to help narrow down the issue.

1.      Check Quarantine and Junk Folders: Check if the emails are being quarantined or sent to the junk folder. Sometimes, legitimate emails can be mistakenly flagged by spam filters.

2.      Email Trace: Use the "Message Trace" tool in the Exchange Admin Center to trace the path of the emails. This can help determine if the emails are reaching your server and where they might be getting lost.

3.      Check the Sender's Side: Ensure that the sender's domain is not experiencing issues. They should verify that their emails are not being blocked or bounced back (Receiving NDR).

4.      Check Block Lists and Whitelisting: Ensure that the user’s email address or domain is not accidentally added to any block lists (both on your side and on the sender’s side). Add the partner company's domain to your allow list to ensure it is not being inadvertently blocked by your spam filtering settings.

5.      Defender Policies: Review the Microsoft Defender Anti-Phishing and Anti-Spam policies to ensure they are not overly aggressive and blocking legitimate emails.

6.      Review Email Filters and Rules: Check again if the user has any personal email rules or filters set up in their mailbox that might be inadvertently moving or deleting incoming emails.

7.      Sender's SPF/DKIM/DMARC Records: Ensure that the sending domain has correctly set up SPF, DKIM, and DMARC records. Misconfigured DNS records could cause the emails to be rejected or filtered out.

By going through these steps, you should be able to pinpoint where the issue lies and take appropriate actions to resolve it.

If the answer is helpful please click on ACCEPT ANSWER as it could help other members of the Microsoft Q&A community who have similar questions and are looking for solutions.

Thank you for your support and understanding.

Best Wishes,

Alex Zhang