Fix Mailbox does not exist error in Microsoft Teams

If you’re using Microsoft Teams, then maybe you have come across a particular error in recent times. It’s nothing out of the ordinary, but annoying nonetheless. The issue we are talking about here is when the mailbox in Microsoft Teams is empty. You may see an error message – Mailbox does not exist.

An empty mailbox, or one that doesn’t exist, would be a surprise to anyone that had content within it before this problem. The big question right now is what caused this to happen, and whether or not if there is a way to fix it once and for all. Now, we can’t say for certain what caused the mailbox to go empty, but we can say the problem can be solved.

Mailbox does not exist error in Microsoft Teams

From what we have gathered, the mailbox does not exist error tends to happen when Microsoft Exchange is in use. Yes, many users of Microsoft Teams take big advantage of Exchange, which should come as no surprise to anyone at this point.

OK, so let’s look into how we can solve the no mailbox error, and hopefully, it will never show its ugly head ever again

Microsoft Teams – Mailbox does not exist

Fixing this problem is super easy, at least from our point of view, so don’t be discouraged because we will make it easy to understand.

  1. Check the O-auth setting
  2. Verify that Exchange Online can successfully connect

1] Check the O-auth setting

The first thing you’ll need to do is run the Test-OAuthConnectivity tool to see if things are working as they should. The idea here is to make sure your organization can successfully connect to Exchange Online because this is a very important aspect.

To get this done, please launch Windows PowerShell by right-clicking on the Start menu button, then select Windows PowerShell from the menu. We suggest choosing the admin version for a better chance of this working.

After launching the tool, please copy and paste the following into PowerShell then hit the Enter key on your keyboard:

Test-OAuthConnectivity -Service EWS -TargetUri -Mailbox <On-Premises Mailbox> -Verbose | Format-List

2] Verify that Exchange Online can successfully connect

The next step, then, is to test if the connection is working, and yes, the task is easy to accomplish. You see, simply follow the steps above to launch Windows PowerShell, then copy and paste the following, and as usual, hit the Enter key:

Test-OAuthConnectivity -Service EWS -TargetUri <external hostname authority of your Exchange On-Premises deployment>/metadata/json/1 -Mailbox <Exchange Online Mailbox> -Verbose | Format-List

That should get the job done, 100 percent. So, go ahead and check the mailbox to see if its back to its regular setting.

All the best.

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