Decline Code 78: Blocked, first use

The decline code “78: Blocked, first use” generally indicates that a transaction has been blocked because the credit card being used is new or has not been used before. Credit card issuers often put certain security measures in place to prevent fraud, and one such measure is to flag and block the first transaction on a new card until the cardholder verifies that the card is in their possession and the transaction is legitimate. The cardholder may need to contact their credit card issuer to verify their identity and confirm that the card is active before the transaction can be processed successfully.