I can only load Serve/Discover at certain old look machine at regular checkout at WM. All the new machines do not work. All the machines at the MC does not work. It seems even old machines are different. At some stores, regular checkout machines are 100% success. At others, the machines give error message by chance--"tender not allowed" at the first try, going through at the second try. I guess it has something to do with the software version?