offline playback says my downloaded songs are not downloaded

[reneehulshoff]

I'm using a premium account on iPhone SE

I've made a playlist.
I've downloaded the entire playlist.
- All tracks got a green download-icon.
I took my spotify offline.
I played the downloaded playlist.
It works for a while (couple of songs)
Than it says the track is not avabable because it's not downloaded.

- The tracks have gray downoload-icons now.
If tried reinstalling, restarting, removing my offline divices several times.

Nothing seems to fix it.

PLEASE  HELP!