Situation: The user has a good Internet connection and enter the correct credentails. However, she has a problem to run Microsoft teams.
Resolution 1: Logoff and re-login Teams.
Resolution 2: Make sure not Windows Update pennding. If so, please install the update wand restart the computer.
Resolution 3: Make sure your date and time are set up correctly.
Resolution 4: Clear Teams cache in %appdata%\Microsoft\Teams
Resolution 5: If it is offline, switch to Available.