I converted several youtube songs to mp3's and then imported those songs into spotify. I can play all the songs on my computer, but when I try to play the same song on my phone, I get a pop up saying "song not downloaded" it then gives me directions to "sync song to this iphone"

1. connect iphone to same WiFi as the computer - check

2. launch spotify on the computer where this song is stored - check

3. mark the playlist containing the song for offline sync on your computer - check

4. watch as your song magically appears on your iphone - no check

I have logged out of spotify, hard reset device and laptop, searched google for answers and nothing is working.