When placing an order I get an error message stating that there has been an authorization failure. What went wrong?

When placing an order I get an error message stating that there has been an authorization failure. What went wrong?

Please double check the credit card number and expiration date on your card. It's also very important that you provide the correct Billing Address that your credit card company has on file. Please be aware that AmputeeStore.com currently accepts Visa, MasterCard, Discover, Amex and PayPal for credit card payments.