Im currently experiencing this problem whilst trying to watch the latest episode of Gotham (broadcast 25/01/2016) via my TiVo box. For the past few days, every time I try to watch the episode, I receive a message stating that, "On Demand is temporarily unavailable. Please try again later" and the 6096 error code is presented. This also happens whenever I am trying to watch (don't ask why) Birds of a Feather.
Strangely, I am able to watch a programme which was on Channel 5 yesterday afternoon/evening?
Very odd, and annoying - given that Gotham is about to drop off in terms of availability!