CVV2 is a new authentication scheme established by credit card companies to further efforts towards reducing fraud for internet transactions. It consists of requiring a card holder to enter the CVV2 number in at transaction time to verify that the card is on hand.
Visa & MasterCard:
This number is printed on your MasterCard & Visa cards in the signature area of the back of the card. (It is the last 3 digits AFTER the credit card number in the signature area of the card).
American Express has a 4-digit security code located on the front-right corner of the card.
NOTE: We are not allowed to save a CVV2 code in our billing database. This is why some credit cards CANNOT be automatically charged.
If you have enough funds, but your auto-payment fails, it is likely because your card company requires the CVV2 for every transaction. The only solution is to use a different card, or pay manually each time.