Hello everyone!

I hope somebody can help me out. I've got some mp3's stored on my computer, and added them to a playlist on the Spotify-app on my computer. I can now play them on my computer. If I open the same playlist on my Android-phone or -tablet, the songs are also added to the playlist. Yet I can't play them, they are in grey text and nothing happens when I click on them. There also isn't a green arrow with these songs, but there is one with every other song in that same playlist. 

My Spotify app on my Android-devices are not on 'offline' in settings, and the playlist has got offline playing enabled. I have a Spotify-premium account, and would really like to listen to these songs while running. I've checked the Spotify Help section, but couldn't find a solution for this.