Administrators may wish to reuse a phone number after a user has been deleted. The portal user may encounter a sync error due to the number still being assigned to another user in MS 365.

Explanation of Behaviour

The issue occurs because the MS 365 admin has deleted the user in the MS 365 admin portal before deleting them in the service portal. This causes an issue since our PowerShell commands will no longer be able to act on the user in MS 365


The reader should always delete the user in the service portal first. The user can then be deleted in MS 365.

However, if the M365 administrator has already deleted the MS 365 user, please restore the user in MS 365 and perform a sync on our portal. This will reallocate the number correctly. The administrator then can proceed with deleting the user in MS365 without an issue.