You can first try restarting your Mac and see if your Teams app is working again. If not, you can continue with the fixes we have gathered for you. Furthermore, you can also try restarting your router if you’re experiencing a bad internet connection.
If an application stops responding, you can close it by using the "force quit" option. Microsoft Word or a web browser may lose all unsaved changes if you use the "force quit" command to close it if it freezes unexpectedly. So, remember that!