Can't join or Create Car Clubs

The msg “An unknown error occurred. Please try again later.” pops up when trying to join or create a Car Club.

Yeah I’m having the same issue. I know T10 is working on their servers so it could be that. I’m able to download the VIP cars now for free and am getting my VIP wheel spins as well. Still no double XP for finishing races but its a good sign that they are hard at work at fixing the games current issues.

you have to finish 3 championship events before car clubs unlock…

That is true, but even when it unlocks I can’t join a club due to an unknown error which is what it sounds like is happening to the OP.