The full error may read Error "Redemption Failed. ERROR. 404 User account not found. Discount Qualification Failed"
This error typically means the program processed the Redeem code and passed it to the server for validation. The server generated an error indicating that the items on the check failed to qualify.
To trouble shoot the rules and ensure you have the line item qualification setup correctly, you'll need the check number or the bar code.
From the Dashboard, navigate to Support >> Settings >> Bar Code
and look it up on the dashboard. then copy the items on the check into the validation check tool on the dashboard."