If a Microsoft Office User has a phone number populated elsewhere in Office and Azure AD Sync is active, this auto-populates the phone number for the User in Teams and can block activation of the User with ConnecttoTeams. The error "Filter failed to return unique result, "[SipAddress : sip:xxx@xxxx.com] [LineURI : tel:+##########]" will appear in the activity feed.

A correctly setup Teams User looks like this in the Teams Admin portal. Phone Number Type: On premises with the Phone Number/Extension you have added.

An incorrect setup will have the number populated in the Phone Number field at the top of the screenshot above as circled in the screenshot below without corresponding info as indicated in the arrows above.

Instructions

If your Teams User does not look like this, please use the following steps to correct it in Azure Active Directory:

1. Login to the Active Directory Connect
2. On a domain controller, open Active Directory Service Interfaces (ADSI) Edit. To do this, click Start, click Run, type adsiedit.msc, and then click OK.
3. Search for the Teams User for whom the attribute needs to be cleared
4. Right-click on the User and then click on the 'Properties.'
5. You will then see the User Details window with several 'Tabs' in the pane.
6. Locate 'Attribute Editor' and search for the 'msRTCSIP-Line' attribute
7. Double click the 'Row', and it should open a popup with a 'Free Form Text Field' containing the value that is populating for the Teams User from the Azure AD Sync.
8. Clear the value and set it to <not set>
9. Trigger an AD Sync; if the AD Sync is completed successfully, the user's value in the Teams Admin Center should now show Empty.
10. After this, Enable Calling should work for the User.