Additional features, settings, or issues not covered by specific Microsoft Teams categories
I had the same issue.
Somehow when logging in Teams asked for my email address, then the next step, which usually is to fill in the password, was skipped and immediatley the error showed up about not being able to connect.
How I solved it:
- Quit Teams,
- Log in with other valid credentials from a different organisation. Wait for app to completely load
- Then log out from those credentials, it will ask for the password after filling in the email address.
- Try the proper credentials, and voila! Worked for me!
So somehow the session got stuck and logging in with another email account flushed those settings after which I could normally log in.
Hope this helps!