I have a grocery store around me that accepts apple pay and it doesn't work all the time. I also am a point of sale software developer and have been developing with a device that supports apple pay. And sure enough it doesn't work all the time on that either. (I tried it a lot) I doubt it is the reader. Is there some sort of thing I don't know on how to get it to work? Do I have to wait a period of time? I cannot nail down why it doesn't work; but it works probably 60% of the time.