I probably have the same issue on an Denon Ceol N8. Also got 'no network connection' when trying to start Spotify yesterday. After doing a reset of the device it won't login to Spotify account at all, without any error message , just starts over the registration/login process.
I have the same problem with DENON Piccolo DRA-N5. No possiblity to connect via Online Music function in my Denon. Is there any official announcemnt from Spotify? Is it any possiblity to contact Spotify and get the confirmation about the problem?