This means your account was suspended. The system has seen something that is has deemed as suspicious behavior that likely is a violation of Terms.
Correct, when flagged you will not earn BAT and can’t receive payments.
As SmartyAadi mentioned, you will need to submit an official Rewards Support Ticket. Doing this will essentially begin an appeal on your flagged account and they will investigate. If they believe it to be in error or if they want to give a "second chance,’ they will reinstate your account.
NOTE #1
Under no circumstance will it ever be revealed what you did to be flagged. So if that ends up as a question of yours, you may as well give up on getting an answer.
NOTE #2
If you don’t have your profile/account restored, you can always create a new browser profile. Your new profile can begin earning BAT immediately. Just keep in mind that if you were doing anything you shouldn’t be, which primarily means abusing Rewards for maximum earnings instead of just casually using Brave as a web browser, then your new profiles/accounts would likely end up flagged again in the future.