Can't sync all local files

[JTCELAYA]

Hello, I just recently bought some music and downloaded it onto my computer. I also downloaded it onto my phone, but when I added some of the music to a playlist in spotify, only about a third of the songs added synced to my iPhone. Also, when I try to connect my phone to my computer, it does not appear under "Devices", what am I doing wrong?

[dinomight]

Are both devices connected to the same WiFi network? The local file sync should be done wirelessly; it doesn't work if you simply transfer songs to the iPhone itself. Spotify has to transfer them over the network, and the app needs to be open on both the computer and the mobile device for the two to see each other and initiate the transfer.