As of 2022, Skype for Business 3PIP phones will no longer be able to connect to Skype for Business Online and will need to be moved to the Microsoft Teams SIP gateway. This is due to Microsoft Teams now being the primary client for Skype for Business Online, and all features have been migrated over to Teams.

If you have any Skype for Business 3PIP phones in your environment, you will need to take action to move them to the Microsoft Teams SIP gateway by the end of July. After that date, the phones will no longer be able to connect to Skype for Business Online and will need to be re-provisioned for Microsoft Teams.

The process to move Skype for Business 3PIP phones to the Microsoft Teams SIP gateway is relatively simple and can be done in a few steps.

First, you will need to unregister the Skype for Business 3PIP phones from Skype for Business Online. You can do this by going to the Skype for Business Online Admin Center, selecting the phone, and then clicking the Unregister button.

Next, you will need to delete the Skype for Business 3PIP phone objects from the Skype for Business Online PowerShell. Running the following cmdlet:

Get-CsOnline3PIPPhone | Remove-CsOnline3PIPPhone

Finally, you will need to re-provision the Skype for Business 3PIP phones for Microsoft Teams. You can do this by going to the Microsoft Teams Admin Center, selecting the phone, and then click the Provision button.

Once you have completed these steps, your Skype for Business 3PIP phones will be moved to the Microsoft Teams SIP gateway and will be able to connect to Microsoft Teams.