Call2Teams - Customers
When adding or reviewing users in the portal, customers may see the following:
The customer has an on-premise Active Directory and is using Microsoft DirSync to sync their users into their Microsoft 365 Azure Active Directory.
If any of those users have the msRTCSip-line attribute set in their on-premise Azure Active Directory then the service will be unable to apply a phone number using the background PowerShell script, until they have cleared this attribute and run another sync to Microsoft 365 Azure Active Directory.
If the service detects this error when doing a Call2Teams sync then it will show advice to this effect below the sync button on the portal.
However it also displays that the user is DirSync'd, as shown above, to aid in troubleshooting and to help the customer avoid having aforementioned error.