If you have received a bonus, you may find you have to satisfy a playthrough requirement before withdrawing any winnings from that bonus. For example, if you entered a promo code when signing up for an account in order to receive a bonus, you may have to satisfy these terms or abide by other restrictions before you can actually withdraw any funds. This sometimes happens with winnings earned via free spins, too. Be sure to read the terms and conditions associated with any bonus.