Payments normally fail when the information provided does not match that which is held by your bank. Here are some things to remember when booking online:
The address and zip code you enter needs to be the same as the billing address for the card. This is where the bank statements are sent.
Please note, the security code for an American Express card consists of four digits on the front of the card. If you have attempted a few times with a card, you may need to close the website and try again later that day as the card may have been made inactive for this site and check with your bank.
If you are still experiencing problems, please contact your bank to confirm you are entering the correct details when attempting to make a booking.