Cant sync some songs to samsung galxy s6 device

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I have a local file with my music.  I can play it on spotify from my destop jsut fine, but when I try to play it on my phone about 50% of the songs won't play and is greyed out.

Edit: I just figured out something, All songs were download from youtube.  the only songs that would play are the ones that already exist on spotify.  When I play a song from my local folder on my phone it plays the spotify version and not youtube version.

Edit #2: Seems that all the songs that wont play has "unknown artist" written under it