Local Files Are Not Syncing anymore

[ifyousoyou]

I don't know what happened but whenever I try to add my music from iTunes to Local Files, it won't play anymore. I add it to another playlist and try to make if avaliable offline but it stays greyed out. I successfully convereted 14 files before but just one day randomly I tried to add one more file and it wouldn't play. I unistalled Spotify and reinstalled it but now not one song out of my local files can be synced. I don't know what the problem is?