FAQ “Unauthorized usage” error when trying to run a transaction, what is this?

When you see such an error it's the cardholder's bank blocking the transactions, not the processor or the terminal. Sometimes the bank sends a message on the cardholder's phone requesting to approve the transaction and he needs to approve it. In case he doesn't, the bank will block it. It depends on the cardholder's bank account settings. The cardholder needs to approach his bank in this regard.