just got this and wondering

You can create a local world in the New Game menu. (Last Tab, alternative "Host a World")

Originally posted by Goblin: apparently it's our problem and not a bug so the dev's dont seem able or willing to do anything about it. i convinced my friend to get it and he liked the game but he's not happy now.

anyway i thought it pretty weird to play a local game with a friend to teach him the game has to be authorized. meanwhile i have no issues connecting to modded servers at all.

Authorization in Eco is done by the server - for local games that is hosted on your own PC. If you can join multiplayer servers that just means that there is a local networking issue preventing backend servers to be reached that needs to be resolved, confirming that backend servers are working correctly for other servers. Connection issues are logged and our support can determine if such is the case, but it's impossible to say what exactly is causing it, only the owner of the PC / network that has access to it and set it up can do. Typically it's VPN's, Antivirus Software, Firewalls, ISP restrictions or temporary issues in DNS, Routing or other parts between client and backend servers that are not under our control.

Eco will offer a limited offline mode after leaving Early Access.