Conversations involving multiple participants, allowing collaboration and information sharing in Teams
In most trouble shooting I always close office products, open excel, Account lower left, update options, update office365.
After update I Turn off "Try new Teams" and "Try new Outlook" to turn off Beta programs. Then I roll back the Teams install to a known working version = Teams_Windows_64.exe. So far these steps have resolved 99% of all trouble shooting Teams/ Outlook issues. Unfortunately using Beta or trial versions on a network can cause other unknown issues.