The 'Restrict Withdrawal Cancelation' feature prevents you from canceling your withdrawals once you've requested them. It's a useful feature that will prevent you from using your winnings for gambling.
If you'd like to apply this to your account, go to the main lobby and select:
Once you activate this option, you won't be able to cancel any pending withdrawals on your account. This also means that we won't be able to cancel your withdrawal if requested.
This restriction is permanent. Once you activate it, it won' be possible to restore your ability to cancel your withdrawals.