Songs Won't Play on Spotify Mobile

[lindsindor]

So I'm really frustrated here. Some of the songs that I've imported into Spotify and that show up on Spotify on my desktop will not play on Spotify Mobile. I have some old songs that aren't in Spotify's library and I'm wondering if that could be why this is happening; though to be honest that would be upsetting because I bought the record and just want to be able to play it with the rest of my playlist I've made. Does anyone know how to fix this?