Check your settings
Often the default setting is to not send CVC codes, especially if you're new to Booking.com. If that's the case, and you need the codes for your business operations, contact the Booking.com team to update this.
It’s good to keep in mind that requesting CVC codes can reduce the conversion rate of bookings at your property, since customers generally prefer to provide fewer details.
AMEX and other cards
We don’t request CVC codes from AMEX card users.
If the card isn't AMEX, and the issue is affecting more than one booking, contact your channel manager to ensure that CVC code details are being passed from them to you.
If your channel manager isn’t receiving these codes, they can contact the Booking.com team to change this.