WP 8.1 synchronisation problem

[teh_dot]

Hi!

Big problem with my Spotify on WP, it doesn't want to synchronize my songs. It detects that I'm connected to WiFi, yet the synchronization status is "waiting". I've tried to restart my phone, I've tried to make every playlist offline/online again, it downloads some of the songs (sic!), with the progress bar showing up at the top of the app, but as it progresses, the number of songs will start to decrease, so that it stops when it "finishes" everything. 

Back in settings it still has trakcs to synchronize (40), yet the status still says "waiting". 

It all started few days ago when I realised that suddenly under every playlist a green downloading bar (filled in ~75%, it would vary a bit) would appear for no apparent reason.

Obviously, the PC version works great. 

The pics with my problem: http://imgur.com/8EaWR2D,w967hu8

[Grace]

Hey teh_dot,

It sounds like you may be out of space. How much do you have available on the device?

[teh_dot]

I'm afraid I have over 18GB memory left. And this is only internal memory, my Lumia 920 doesn't have a microSD card.

[Peter__]

Are there any local files in those playlists from your computer?

[teh_dot]

No. They are all from Spotify.