Can't set up a LAN game

Ok, I’ve been trying to set up a LAN game between me and my friends laptop on GMod (nothing fancy, just literally an ethernet cable from one computer to the other).

But whenever we start a game, it loads up and everything, and we can play for maybe 30-60 seconds, then the game stops and whoever was host gets a message on the screen saying “kicked by console: invalid steam ID” or something along those lines, and the other player loses the connection as a consequence.

But… I DO have a steam ID (same as my username here). So does my friend. We tried several times and always the same result.

I get the feeling there might be something simple but vital that I just haven’t thought of, but I’ve absolutely no idea what, so any help would be greatly appreciated:)

How odd. Have you both logged out and back in?

Well we weren’t logged in online obviously, because the ethernet port is being used for the LAN and theres no wireless in the house, but we tried on two seperate occasions, so i suppose technically we logged out and back in…

You need to be connected to steam to go multiplayer.

Bollocks. Thought it wouldn’t matter if it was only a LAN game. Ok thanks anyway.

Was your friend on his own account?That could be the problem…PIRATE!