So it stopped syncing, a few days ago. I've used spotify premium for almost a year now and never had a problem on my s5, I just upgraded to my new s6 and it synced fine for awhile. Now whenever I'm on my home wifi spotify refuses to access the Internet, everything else gets through. If I switch to 4g it works fine but I have over 5gb of music to download to my new phone. I am yet to try downloading music over a different wifi. It seems to be a conflict between the app and the s6. If it was a router problem then the other phones in the house would have issues with their spotify but that's working fine. I've deleted the cache and all data and reinstalled the app a few times.