What does 'Cardinal Authentication Required' mean?
This means that your customer's card Bank Identification Number (BIN) which is typically the first 6 digits on their bank card, does not support 3-D Secure Authentication.
3-D Secure Authentication, also known as 3DS or 3DSecure is an extra level of security to ensure that every transaction done with a card is authorized by the cardholder. This is put in place to reduce fraudulent activities for Card Not Present (CNP) transactions. You can find more information about this here.
What can I do about it?
Kindly have the customer reach out to their bank to get their card enabled for 3-D Secure Authentication.