First, I would try rebooting your phone. If that does not work try logging out of the Tesla account via the app, log back in. If that does not work then try deleting the app, reinstalling the app.
I recommend that every Tesla owner set up 2-factor authentication on their Tesla account. You will need to use Google Authenticator or Microsoft Authenticator. You can also use Authy (Authy uses Google's Authentication Service, Authy adds features such as secure backup for your authentication credentials if you need to reinstall.)