When attempting to connect to an Open LAN Minecraft session\game on my local network, I receive the message "the authentication servers are down for maintenance.".

This message doesn't make sense since the game I'm attempting to connect to is an offline game (not Internet connected). There's no reason for authentication against any server.

Why can't MC be played on a local network without Internet connectivity?

And just to confirm, an Open LAN game doesn't require Minecraft server, correct?