Originally posted by Yakumo_2020:

it appears that the update IG released today to enable something called "crossplay" breaks the server side of the game (even local it has a client:server setup).

From the variouse comments in these forums the patch has also borked the hosted and personal dedicated servers as well as local play.

At this time it looks like the only thing we can do is wait for IG to fix the problem. And hopefully learn from this incident and do better testing of patchs before pushing them out to players.

That can't be completely correct. I can play local right now without problems at all for example.

At least one mod is causing problems for people.
Also, there seemed to be an issue where a .bat file had the file extension removed in the game, so it wasn't being read correctly. Adding the extension made it work again.