After the word hit this past May that Disney was closing down Avalanche Software and ceasing further production/development of its Disney Infinity franchise, it was only a matter of time before they laid out their plans to bring down all of the online infrastructure. Enjoy your time in the game now, while you can, because next March, it'll pretty much be over.
I've read through the news post they put up about all of this on their website, along with their FAQ, and I'll be honest, parts of this are still confusing. So if you own the game and are concerned about being able to play it still, I strongly recommend you hit up both places and read for yourself. That being said, here's the breakdown of events leading up to the big shutdown on March 3, 2017, and what it means.July 29, 2016 In-game purchases for the PC, iOS, Google Android, Amazon Android and Apple TV version of the game were removed. This was done as these versions will be entirely unplayable at the end of September (more on that in a bit). In-game purchases for the Disney Infinity 2.0 version of the game on Steam have been removed. You can still make in-game purchases for the Disney Infinity 3.0 version of the game on Steam, BUT YOU PROBABLY SHOULDN'T. While both the 2.0 and 3.0 versions will still be playable, they will no longer have any online functionality starting on September 30. As this is the only way to play co-op, you'll be left with a single-player only game.
I gotta say, it's pretty cold of a company to provide you with the opportunity to continue buying content for a game that will either be entirely or mostly unplayable in a few months time. That's kind of a new low. So consider this post a pretty big "caveat emptor" if you currently own any non-console version of the game.