I'm having a strange problem with a shared mailbox ([email protected]) in Microsoft 365—specifically, the inbox rules aren't running automatically when new emails arrive. However, when I manually run the rules, they work perfectly fine. I've tried a whole bunch of troubleshooting steps already, including ensuring the Full Access permissions are set up correctly when accessing the mailbox via 'Open another mailbox' in Outlook Web. I've also created the rules directly in OWA, kept them simple (e.g., moving emails with the subject 'specialtest123'), confirmed that the mailbox is a Shared Mailbox (not a user mailbox), ensured no transport/mail flow rules are interfering, performed a New-MoveRequest to refresh the mailbox, and even recreated the rules afterward. Other shared mailboxes in the same tenant are operating as they should. I'm at a standstill and wonder if anyone's faced a similar situation and found a solution beyond what's documented by Microsoft. Any insights would be greatly appreciated!
4 Answers
One possibility is that someone else might have a local "client-side" rule that overrides your shared mailbox rule. It's worth checking with other users who have access to see if they have set up something inadvertently that might be causing a conflict.
Another option is to create a new shared mailbox and test the rules there. It might be easier than digging through the issues of the existing one.
If you haven't yet, you could try the nuclear option: Export your shared mailbox to a PST file, delete (or rename) the mailbox, create a new one, and then re-import the data along with your rules. It’s a bit drastic and risky, but it might just fix the issue if everything else fails.
Yeah, sounds risky, but desperate times call for desperate measures!
I recommend considering Power Automate instead of traditional inbox rules. Inbox rules run under the context of the mailbox owner, but shared mailboxes lack a user identity, which can cause reliability issues. Power Automate can trigger processes more consistently when new messages arrive without depending on mailbox session states or user roles. If you use a dedicated service account for automation, it helps mitigate potential problems if someone leaves the team. I can share an example setup if you're interested!
Could you back that up with some documentation? I heard Power Automate flows can take up to 5 minutes after delivery to execute.
I get that, but I really want to resolve the problems with the existing mailbox!