Provided by your bank, 3D Secure is an extra layer of security for online transactions, commonly referred to as "Verified by Visa" or "Mastercard SecureCode".
After you have entered your payment card details, a pop-up will be loaded by your bank. The appearance may change slightly from bank to bank, but you should expect the following information:
Please enter the information requested and click 'submit' to authenticate payment.
If you do not know your password (or you have not set up 3D Secure) you should follow the instructions on the page. If you cannot see instructions, or you have any questions, you should contact your bank, who should be able to help.
If your bank does not offer 3D Secure, please contact the team running the event you are trying to register and pay for to discuss alternative ways to pay.
There may be other reasons why your booking fails. If you are unsure why your booking is failing please contact the team running the event you are trying to register and pay for and they will be happy to help.