Songs won't automatically advance

I copied all of my music from iTunes onto the SanDisk.  I can play each tune individually, but they don’t advance from one tune to the next - I have to manually do it.  Any suggestions or am I hoping for too much? 

Thanks

do you have the files in separate folders? If so the iXpand Sync app does not continue playing from one folder to the next. If you put all the music files in one folder the app will automatically go to the next file in the folder and will stop playing after the last song in the folder.

No, they aren’t in separate folders - 

What I have discovered is that the songs WILL advance on my iPad, but not my iPhone 6