Joiplay has it's own set of issues that can prevent it from working properly. Have you tested other games with Joiplay to see if it's the culprit and not Headmaster?
I don't know then, as I don't use my phone for any kind of gaming. All that I know about joiplay is what I've seen people comment about it here, and a large number of those posts complain about it not working properly with the games they're trying to play.
