This is likely due to Samsung's recent software update. They've enabled a variety of power saving features, which may have cut HyperDrive® from running in the background. To check some of your battery settings, go to Settings -> Device Care -> Battery -> 3-dot button in top right -> Settings. From there, make sure HyperDrive® is NOT enabled under Sleeping Apps. It would also help to uncheck Adaptive Battery if you don't open HyperDrive® very often.