It appears that Slingbox no longer supports the Amazon Fire TV and Fire TV Stick for their Slingplayer app. The app first arrived on the platform in late 2014, but it has now been removed from the Fire TV appstore. Users with the app installed are reporting the Slingplayer app no longer loads. Amazon’s support is telling customers that the app is no longer supported. Changes in the latest 18.104.22.168 Fire TV software update may be the source of the app’s new incompatibility, which means we may see the app return once these issues are adressed.
6/28/2016: The Slingplayer app has just been re-released.
7/1/2016: The Slingplayer app has now been removed again.
7/6/2016: The Slingplayer app is back once again.