Did you happen to use an app hide feature at some point? My Denon and Onkyo avrs have had a few revisions over the years for the Pandora and Spotify apps, sometimes rendering it useless for months at a time until update issued. At some point they probably just don't update you but you could also try resets (soft first, then microprocessor/factory). The only time I had the actual app icon disappear was on my Denon for Spotify when they updated to Spotify Connect status (I can still use it, just nothing on screen on the network setting, but Onkyo never issued the Spotify update so I have the icon but no functionality).