Decline Code 1A: Additional customer authentication required

The decline code “1A: Additional customer authentication required” for a credit card transaction indicates that further verification is needed to authenticate the cardholder’s identity before the transaction can be approved. This typically happens under protocols like 3D Secure, where additional steps are required to ensure that the person making the transaction is indeed the legitimate cardholder. This may involve the cardholder having to enter a password, answer security questions, or complete a biometric verification, depending on the card issuer’s security settings. This additional authentication helps prevent fraudulent transactions and increases security for online purchases.