When you have a balance available under “locked funds,” it means that there is an active bonus to which the balance is locked.
When the funds are locked, it is not possible to request a withdrawal until the wagering requirement for the respective bonus has been met. Sometimes the money is also locked to a specific product, such as Odds, Casino, or Poker, and then you need to play on that product in accordance with the bonus terms and conditions. The specific requirements are always found in the Terms & Conditions for the promotion or in the notification you have received on the website/by email