Problem solved for me :-)
The problem was that the built in speakers became completely dead, not only in Teams but for all applications.
After re-installation of all audio related drivers it worked for a while but after using Teams it happened again.
It turned out while investigating another problem, (login in Outlook) that I had fast start up enabled.
Turning off this option cured two problems. The speakers are now working.
So the fast start up option seems to do a lot of harm. It caches more than it should I think.
Power options -> System settings
Uncheck the: Turn on fast start up (recommended)
You might need to press : Change settings that are currently unavailable
The computer will take a little bit longer to boot, but I can live with that.
/UL