st3fun1

I recently bought ets2 mainly for the multiplayer experience. So i installed the multiplayer mode but every time i start it i get this error "Cannot validate game version". I tried changing the game version on steam using betas menu, i tried reinstalling both the game and the mod, i unlocked the ports in windows firewall. I have no ideea what to do anymore to make it work. EDIT: I found the problem but i cant correct it. My game version is 1.21.4s and i cant downgrade it to 1.21.1s in any way possible.