Teams Service unavailable for CsPhoneNumberAssignment

IBN 4,356 Reputation points

Hello Teams Community,

Please I need help on this issue.

Migration was done from Skype for Business On-Prem to Microsoft Teams online yesterday.

After the migration, some users lost their phones and we tried using the PowerShell command to reassign the phone number back to the users but we got an error


We were able to set the phone number for the user below with the command “Set-CsUser -Identity -LineUri “tel:+40000000”.

After a while, the number is now shown in Teams Admin Center and the user is available for external calls.

But with this command “Set-CsPhoneNumberAssignment” is still the same error.

Users are losing their CsPhoneNumberAssignment. While trying to reassign it we get the error shown in Screenshot.

Microsoft Teams
Microsoft Teams
A Microsoft customizable chat-based workspace.
9,371 questions
0 comments No comments
{count} votes

Accepted answer
  1. JimmyYang-MSFT 49,736 Reputation points Microsoft Vendor

    Hi @IBN

    Please make sure this cmdlet is currently not supported for customers and tenants that are or have been enabled for Regionally Hosted Meetings for Skype for Business Online.

    Meanwhile, please check your Teams PowerShell module is 3.0.0 or later.If a user or resource account has a phone number set in Active Directory on-premises and synched into Microsoft 365, you can't use Set-CsPhoneNumberAssignment to set the phone number. You will have to clear the phone number from the on-premises Active Directory and let that change sync into Microsoft 365 first.

    If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
    Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

0 additional answers

Sort by: Most helpful