pin_set_operation_id reference returned earlier.400 INVALID_OTP_FORMAT - OTP format is invalid (must be 4 digits)400 OTP_EXPIRED - OTP has expired. Please initiate a new operation.400 OTP_MAX_ATTEMPTS_REACHED - Maximum OTP verification attempts reached. Please initiate a new operation.400 OTP_VERIFICATION_FAILED - OTP verification failed (generic error)400 OTP_INVALID - Invalid OTP provided. Please try again.404 CARD_NOT_FOUND - The card is invalid. Please use a valid card.404 OTP_OPERATION_NOT_FOUND - The operation ID is invalid. Please use a valid operation.422 OTP_OPERATION_WRONG_STATUS - OTP operation is not in correct state (already completed or failed)503 SERVICE_UNAVAILABLE - The service is currently unavailable. Please try again later.