Occasionally the Teams desktop app will notify you that its "ran into a problem". Then it can become unresponsive for a while and get stuck. If this happens to you, then give the troubleshooting steps in the video a try!
Methods outlined in this video. Watch the video for step-by-step directions.
1. Try using the web application
2. Clear the Team's application cache
3. Check your network for stability
4. Try creating a new Winwdows user account to test if it's the user account.