I'm having a weird issue where one of my users is receiving duplicate emails from the same sender. In the Exchange Admin Center (EAC) message trace, I see two different message IDs with the same date and time. One shows both 'receive' and 'deliver' events, while the other only shows 'deliver'. There aren't any mail flow rules in EAC or Defender that I can find. Has anyone experienced this before? I'm stuck trying to figure out the cause!
5 Answers
I've got it figured out! It was actually due to an account notification setting from a specific website that had both email aliases saved.
It really does seem like something's off on the sender's side. Could be a glitch in their system.
Could also just be that the sender is accidentally clicking send twice! It happens more than you'd think.
I've seen this happen when there’s a rule that forwards a copy of emails to another service for signatures. In that case, you'd get one email with the signature and one without. Could be worth checking if your user’s setup has something similar!
It sounds like the problem might originate from the sender's side. If they're sending the same message twice but with different IDs, that's usually an issue on their end.
That definitely points to a signature service being misconfigured. It could be anything, really, like an issue with inbox rules or a problem with the email connector. Just keep an eye on it!