Local files not showing (not even as greyed out)

[sorkas]

As the subject says... Previously I've always been able to put my local files that I want synced into a playlist and it has synced with my phone. But now, when I've bought a new phone the playlist is empty. It shows up as a playlist and it shows the number of songs in it but when I tap on it the playlist is empty. 

It works on my laptop, from that one I can see the playlist and sync it...