Outlook(Office365, E3 license)- Receive multiple same messages when sending to someone

Question

Hi, I'm a IT guy in a company but I got a message from a user that in the outlook, recently she receives same message sent by herself in a receive box when she send to someone. even re-creating the profile or changing PC, nothing has been changed so I think this is not issue in client side. is there any possible causes?

Answer 1

Best run a message trace, it will show you how and why: https://learn.microsoft.com/en-us/microsoft-365/security/office-365-security/message-trace-scc?view=o365-worldwide

Answer 2

Hi @Kamiya ,

Agree with @Vasil Michev , message trace should be a perfect method to carefully troubleshoot your issue.

By the way, as I know, Outlook rules or Exchange mail flow rules may also cause issues like yours. It is suggested for you to disable all your Outlook rules and mail flow rules to see if the issue has any difference. You could found your Outlook rule via Outlook > Home > Move > Rules > Manage Rules & Alerts. For more information about Exchange mail flow rules, please check Manage mail flow rules in Exchange Online.

Hope these can help.

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