I am having the same issue (Ubuntu 20.04).
It's very annoying.
Can Microsoft fix this ?
since last week I'm unable to access my work account on linux Teams app. The app is refusing my login information that I provide when it is 'Taking you to your organization's sign-in page'.
Web client have no problem regarding this, I pass STS with success. I can also successfully log in to my student's account from app, which doesn't have any STS.
❯ pacman -Qs teams
Microsoft Teams for Linux is your chat-centered workspace in Office 365