3D Secure (3-domain structure) Authentication, also known as a payer authentication, is a security protocol that helps to prevent fraud for online credit card and debit card transactions.It allows banks to request extra details from a cardholder to verify an online transaction / purchase.

So it may be possible the card company / bank is asking for a one time password (OTP) which is sent to the registered mobile number or email ID of the card holder and if it is entered incorrectly while making the payment. Then the transaction will be declined by the bank. The OTP is valid for a limited time so it needs to be entered at the moment.