A tagged transaction is a unique type of transaction associated with one sent previously. The main benefit is that the 'tag' or distinct identifier is sent to the system in place of sensitive card details. The "Invalid Transaction Tag" response is usually displayed when the tag sent does not match the transaction previously sent - for example, Tag A was returned from First Data Payeezy Gateway with Purchase #1 but Tag B was sent by the merchant with Tagged Refund #1.
This can also occur if the transaction that is being refunded or completed is too old (customers have up to one year to refund charges and around 5 days to complete pre-authorization type transactions). If you believe you have received this message in error, please contact us.