There are several reasons why:
① The transaction amount exceeds the available credit limit of the account.
② The card on file has been renewed or voided and is no longer valid.
③ Credit card account number contains more than 16 digits.
④ Please contact your bank and ask them to cancel the credit card authorization or find out why they declined the charge.
⑤ If you believe any of the issues above are preventing your order from being completed, please contact your bank for further clarification and instructions.