Correcting a user/shared mailbox ID - both using the same

Question

Seeking help please as ive spent hours trawling through this error - I have a shared mailbox and a user that both have the same 'user ID' - this is causing calendar events ONLY to be delivered to both mailboxes.

I have checked email delegation, forwarding, aliases with no result working.

In Exchange Admin, when I select the user, then Edit --> Edit Contact information it shows the user ID as the shared mailbox email address. I have been unable to change this or find how I could do this in PowerShell either.

Has anyone any ideas how to fix?

Answer 1

Hi @Nicolas Jarvisto

From your description you are using Exchange Online, do you have an Exchange hybrid deployment?

If not, please access Microsoft 365 admin center with an account which has permission (for example global admin account).

In Microsoft 365 admin center, locate Users>Active Users and select this user, under the Account tab select Manage username and email:

Correct the username here (and also primary email address and alias if these fields have incorrect values):

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