MP50 Phones not dialling

[Oksania]

Hello,

I recently deployed some Yealink MP50 USB phone devices to my agency users who are on Teams Voice. For some, the MP50 works perfectly: plug and play and away we go.
Unfortunately, for most users they can't start, answer, or end calls but the pause/resume and mute/unmute work fine during a call.
- If they start a call from the phone's controls it looks like it is attempting to dial out but nothing happens on the PC and it eventually ends
- If they receive a call it shows up on the MP50's screen but the answer and decline buttons do not work and neither does pressing speakerphone or picking up the handset.
- If a user starts or answers a call on the PC they can use the MP50 for microphone and audio
- Picking up the handset switches it from speakerphone to handset,
- If I do a test call on the troubled setup, Teams displays a banner saying "No device call controls. Exit other calling apps so you can use your device call controls with teams.
To me, this eliminates the possibility of the device, the PC, the Teams accounts, and the Domain account from being the issue and just leaves it to being an issue with the local Windows profile on the PC.

I hope someone can provide some other troubleshooting options. I may have to look at alternatives, but what from I've seen it sounds like most other phones run Teams as a separate instance, creating several other drawbacks, or else have to be dumbed down to operate similar to the MP50 which makes them a waste of money.

Thanks