Free-to-play mech 'em up Hawken shut down its PC servers in early 2018. Alas, even the solo modes were lost to PC players as well when it was removed from Steam. Hawken didn't have the most inspiring run on PC. It spent five years in early access, changed developers multiple times, and wound up with uninspiring concurrent player counts for a multiplayer game. Still there are some fans who aren't willing to let the mechs stay dormant. They've managed to get a couple singleplayer game modes working again.
The fan-run project Hawakening has a step-by-step walkthrough for folks who owned Hawken on PC that want to jump back in the cockpit. There are no multiplayer servers of course, but there are some game modes that you can play against AI opponents. The folks behind Hawakening say in the video below that as far as multiplayer goes "we haven't figured that one out yet, though we are on our way."
As for the legitimacy of the homebrew revival, the Hawakening folks believe they're properly falling within legal bounds that allow license holders (meaning anyone who owned it on Steam) to make the singleplayer portions of the game operable.
"There's a US law that allows license owners to make the game work for singleplayer experience," they say. "Since this is effectively singleplayer, and you should own a license if you played the game on Steam, you are completely safe to do it."
Hawakening isn't being made with approval from 505 Games, a detail you'll have to agree you understand when signing up at hawakening.com. In the video's description though, they mention that they do want to "open talks with 505" about the fan-run revival. They don't specify the goals they'd have for that conversation, though I imagine an official blessing for fan-run private servers might be on the wish list.
Check the very thorough walkthrough above if you've got a copy of Hawken lying about on your hard drive that you're dying to dust off.
Ta, PC Gamer.