Songs will play on desktop but not on my phone

[jbron]

Hello, 

I have looked at forums to see how this question has been addressed but all are a bit different. It appears that my local files which play fine on my computer (macbook pro) will not play on my phone. 

They are indicated to be downloaded as the playlists I have are all downloaded, yet the songs cannot play. This includes Rihanna's ANTI album. Obviously, I can find this album on Spotify separately using data, but I don't want to have to go through all of my playlists to replace my local files with spotify's files. Is that the only solution to this? Shouldn't spotify be able to automatically know what local files match up with their own? These local files are all bought from iTunes, so it shouldn't be any different. 

Please let me know what I can do because it's quite frustrating.