Cross Tenant Sync and Teams calling

Question

Hi

We have a cross tenant synchronization with another tenant.

Everything works fine, except Teams calling.

In the teams voice app I search for the name of a cross tenant synchronized user and the account shows up. But I see it in the following format first.last_Domain.com#Ext#.
When I choose this account and then click on Call, it doesn't work.

It looks like the call is being directed to the local tenant Teams instance and not the Teams instance in the target tenant.

Is that an expected issue in this scenario?

Regards
Peter

Answer 1

Hello Peter,

I'm facing the same issue, but hopefully there's a workaround.

If you setup call forwarding (or simultaneous calling) from the iOS Teams app (maybe the Android one too, I did not test) and when prompted to enter the name of the target Teams identity to forward calls to, be sure to type the complete UPN (usually the e-mail address) up to the last character.

At this moment you'll see a second identity proposed (the first one is the guest identity in your local tenant) and choose this one.

We've been doing this for many users and it seems the only to set this up. (Actually it used to be possible from the Windows version of Teams about one year ago but is not longer possible).

Answer 2

@Peter

This behavior is expected given the current capabilities and limitations of cross‑tenant synchronization for Teams calling.

When you synchronize users from another tenant, many attributes (like display name, presence, etc.) are brought over so that the user appears in your Teams environment. However, for voice and call routing scenarios the situation is more complex. The call routing logic in Teams is tied to tenant-specific configurations and policies, and, in a cross‑tenant scenario, the system isn’t set up to automatically forward or route calls to the target tenant’s Teams instance. That’s why you see the normalized name (first.last_Domain.com#Ext#) and why the call attempt ends up trying to reach a local tenant contact rather than establishing the connection with the user’s actual calling service.

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