Local files not playing when transferred to another phone

[Timchang920809]

Hey everyone. So I currently have an issue where I just upgraded my phone (from 6S to 7 Plus) and when the process of syncing my songs onto my new phone was finished, I found that the local file songs I had on my 6S, though Spotify says they're all downloaded onto my 7 Plus, will not play on my 7 Plus. Any reasons why and is there a way to fix? 

Thanks!