If your card was blocked after three incorrect PIN attempts, you can unblock it through the app:
Go to Cards in the left sidebar
Select the blocked card
Look for the unblock option in the card settings or the Physical Card section
After unblocking, your next transaction must use chip-and-PIN (not contactless) to reactivate the card. If you can't remember your PIN, you can view it in the card details section (you may need to verify your identity first).