Microsoft Teams - Log In, Log Out And Log Out Again

Start teams by clicking on the app and your windows login is being recognised. This will give you background process for teams and the teams app as you might expect!

The Quit and the Log out options both will end the back ground process, but the log out will restart it for you so that you can login.

Get the login window that gives you the option to login. This now also gives you the option to login to a different tenant.