Why am I having trouble logging in?
If you are using your Twitter username to log in, please try logging in with your email address or phone number instead. If you are using your email address or phone number, please try your username instead.
If the above doesn‘t work, try logging in to Twitter using Safari and then try to log in again with Tweetbot.
Finally if none of the above works, try disabling 2FA, logging in, and then enabling it again.