IIUC no longer attempting to build a proprietary enterprise back end (and their work on that now free software) or a large business, though no shutdown.
Some discussion at Sandstorm is returning to its community roots | Hacker News
Sandstorm is still a great project. They are trying to solve technical barriers to making self hosting something for the masses (I’d be much less skeptical of self-hosting if such existed). I hope it finds lots of success, even more so now!