The online servers are back up, for now, though the devs are still looking into some issues on the Asia Pacific servers.
The servers are back online now, but what on earth went wrong?
When the servers went back online yesterday, they immediately hit their all time peak of concurrent players of 127,542 (back in early access their peak was only 1934).
It’s worth noting that even when the online mode isn’t working you should still be able to play offline.