In most instances when a card is declined, it is due to a restriction placed on your credit card by your card-issuing bank.
Such restrictions may include a cap or maximum amount on online transactions, not allowing currency conversions, border limitations (i.e. blocking transactions outside your country of origin), etc.
Unfortunately, there is nothing we can do on our end if your credit card has been declined upon checkout so you would need to contact your card-issuing bank in order to remove any restrictions or to pre-approve a purchase that you want to make on our website.
If you have any more questions regarding the credit card decline, please contact us at firstname.lastname@example.org.
Our customer support team will reply to your email within the next business day.