Samsung Galaxy J5
My Question or Issue
I was on a holiday for 2 weeks and about 90% of my downloaded music didn't work. I tried downloading it again a few times, but nothing seemed to work. The songs do work when I'm online, but not when I'm offline (which was the whole trip). I'm leaving for another thing in a few days and I'll have to be offline for 3 weeks again then. Is there any solution to this or any reason why my songs aren't working anymore?