Charges can get declined for multiple reasons, usually they are:

1. Not enough funds on the card to complete the transaction.
2. Some banks may reject a charge if the amount is high ($500+) and it's a non 3-D Secure transaction.
3. CVV or card information is wrong - users often make mistakes when typing.
4. Expired card

We also support 3-D Secure, which can reduce charge rejections.

If you are interested in implementing 3-D Secure, visit this page: 3-D Secure