Error: 15004 Gateway decline. What's going on?

This error occurs because the Credit Card Verification Number (CVV) entered is different from the one on the credit card. This error also occurs when the card's expiration date is incorrect.

To resolve this issue, double check associated card data:

• the length of the CVV number depends on the card (three digits for Visa, MasterCard and Discover and four digits for American Express),
• the expiration month should contain a zero if applicable,
• the expiration year should be four digits and equal to or greater than the current year.