Accessing and using Microsoft Teams on smartphones and tablets across platforms
I've been having the same issue for approximately a week. Pixel 3 XL with April's Android updates.
I have not been able to fix it by turning off WiFi.
What I DID see work was when the issue occurs, quit the Teams app, then open and close the Microsoft Authenticator app. Then open the Teams app again. FYI - when this happens to Teams, Outlook and To-Do also break for me. As someone above said, it seems the commonality is Authenticator.