When I try to register for multiplayer I need a game key. I have found a serial key on my gog account. But that didn't work.
Anyone that can help?
What format should the key be in. My brothers code was 0000-0000-0000 that he got from steam. But my code is far longer.

I join to ottebrand. I bought this game and I can't register for multiplayer, because I do not have a key. WTF?!
Where can I find a game key for multiplayer???
Date of purchase: 2016-12-04
Order number: #be73a92309f5

I'm on the same problem... Where the heel are these key ?

I resolve this problem. I find a key on my gog account on gog.com, NOT on GOG Galaxy.