Teams Voice on Mac - Couldnt connect you - internal calls - macOS Monterey

Hi everbody

we see the following problem on more and more Macs running macOS Monterey (12.x doesnt matter what build)

- users can not make phone calls to other internal users of our organization (same tenant) when they click the phone icon to initiate the call. Error message "sorry couldnt connect you".

- it works when using the arrow sign on the right of that button and choosing the users phonenumber.

- they can receive calls internally

- they can make in and out calls to the public phone network (Teams Direct Routing setup)

- it doesnt matter if they are in the office on the corporate network, connected from home via vpn to the corporate network, on the road via mobile hotspot.

- it doesnt matter if its a Mac with an Intel processor or if its a new machine with a M1 processor

the only thing they have in common -> the are all running macOS Monterey (various builds).

we are also running various versions of the Teams client for Mac.

i can not find the call tries anywhere in a log to find out what went wrong.

anybody seen anything like it?

cheers

Jürg, Zürich, Switzerland