Microsoft Teams has been blocked for UCAR since the adoption of O365. Attempting to sign into Microsoft Teams with your @ucar.edu account will fail. You may attempt to join Microsoft Teams meetings with a personal account, or a guest account (no login) if the meeting was setup to allow it.
Here are instructions for joining a meeting without logging into an account, note that you may need to perform these instructions from a private browser session:
Or you can sign up for a personal account here: