I've got Spotify working perfectly on the desktop, iPad, through Sonos and on one iPhone. On the second household iPhone, it was working fine for several weeks - now it will display the playlists, starts to play but stops halfway through the first rack played and then will not play any further tracks. None of the other devices are logged in to Spotify. I've logged out and in, de-installed and re-installed without success. Any suggestions very welcome - my first post here.