Well, brainly support is a known fail so don't even try to email them or send in a report because they won't reply. Try restarting your device or maybe come back to it in a couple of hours. Their servers may be swamped if you've given the site too many commands at one time, or if there are a lot of people online right now. There may also be a bug or it may not be letting you in because it thinks you did something wrong.
