Shared Mailbox and a rehired user

CJ - CFS 1

We have a user that left the company a few years back and we deleted his user account out of AD and then added them to our formerrep@ shared mailbox as an alias. That employee has since come back and we recreated his AD account. When we gave that account a license it automatically deleted the formerreps@ shared mailbox that the user was aliased to and added it as an alias to that user.

Was wondering if others had experienced this, is it intended behavior or something of the like?

KyleXu-MSFT 26,206 Reputation points

2022-11-07T06:27:39.313+00:00

@CJ - CFS

Are you running a hybrid Exchange organization?

Could you provide detailed information about how this shared mailbox and new mailbox created in your organization? I will try to test it in my lab.

1 answer

Andy David - MVP 141.2K Reputation points MVP

2022-11-04T19:28:06.707+00:00

Never heard of that or know of any way that is possible. The mailbox was deleted? That isnt something that 365 would do.
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1 person found this answer helpful.
CJ - CFS 1 Reputation point

2022-11-04T19:31:04.807+00:00

I ran a test with a brand new user and a brand new shared mailbox and did the same exact steps. I was able to duplicate it where it deleted the shared mailbox when I added the license to the user that was aliased to that mailbox. Seems like a huge misstep to me but I wanted to make sure it wasnt intended to do that.

Andy David - MVP 141.2K Reputation points MVP

2022-11-04T20:10:35.927+00:00

Can you provide all the exact steps you are doing? Maybe then it will make sense.

CJ - CFS 1 Reputation point

2022-11-07T14:45:11.773+00:00

Created a user shared mailbox

Created a test user

Gave the test user a license.

Tested to make sure email works to that user and the mailbox is accessible.

Deleted the user out of AD.

Verified the user is deleted and added it as an alias to the test mailbox.

Once the alias took in AD and synced to the office admin portal I tested the alias and it worked just fine to email to and it went to the shared mailbox

Then recreated the user.

synced the server

Checked the office admin portal and both the user and the shared mailbox existed simultaneously.

Once I gave the user the license and the server synced the shared mailbox disappeared and is no longer accessible.

Tried to log in and got an error that says shared mailbox "no longer exists."

The shared mailbox had become an alias on the user account in the office admin portal and the mailbox ceases to exist.

KyleXu-MSFT 26,206 Reputation points

2022-11-10T08:45:45.317+00:00

How this shared mailbox created? Whether it is created on Exchange online directly?

CJ - CFS 1 Reputation point

2022-11-10T17:47:39.197+00:00

We create all of our shared mailboxes in the office admin portal

KyleXu-MSFT 26,206 Reputation points

2022-11-16T08:51:59.113+00:00

Based on my testing, this phenomenon doesn't occur, when I try to assign license back to new created mailbox, this error will show:

CJ - CFS 1 Reputation point

2022-11-16T14:50:44.017+00:00

That looks like an AD error, is that correct?

If so then you use AD for your shared mailboxes and do not create them as just an non-AD synced user.

KyleXu-MSFT 26,206 Reputation points

2022-11-28T06:47:29.84+00:00

No, it isn't an AD issue. the Office 365 find this emails address is being used on a shared mailbox. Office 365 will prevent to assign license to another mailbox which using this same email address.
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