Can't listen to Local Files on my Mac/iPhone

[sregula1]

On my Mac, the "Local Files" playlist is visible, with all of my music in it, but spotify won't let me make the playlist available offline. Because of this, when I use spotify on my phone, none of my local files are even visible.

I looked it up on the spotify help page, and it said that some files that are downloaded from iTunes are in a protected format and might not show up. What does this mean/anyone know how to solve this??

SOS help please