This means our payment gateway (the service that processes the payment) was unable to complete the transaction.
There are a few reasons why this may be the case. If your bank has two factor authentication you may have failed the authentication step. Or you may have entered incorrect card details (the most common being incorrect expiry or security code). The issue could even be that the country your card was issued from is currently under santions.
If you do experience this error the best thing to do is to retry the purchase, being sure to double check each detail before you submit your order.
If you still cannot complete your order please contact our support team, please quote the error message and give a description of the issue as you are experiencing and we will investigate.