Additional features, settings, or issues not covered by specific Microsoft Teams categories
I had a similar issue on my Android mobile Teams app. I have multiple profiles (accounts) for different clients, and the mobile app allows me to easily switch between the accounts. I just rolled off a project, my Domain and O365 account for them were deleted, and the mobile Teams profile was set to that client, so the app was continually asking me to log in, there was no way to get past it to delete the profile. The solution from skrasher above worked, all I had to do after clearing the cache and data was launch the mobile Teams app and sign in with my Teams account, then I could add back in all the other profile accounts for the other clients.
Microsoft DEV team---there has to be a way within the Teams mobile app to get around this issue of an invalid profile (account), something like a cancel button on the non-existent account login screen to get back to the active Teams profile list?