Plutonium

Hello everyone, whenever I try to load into a server, I always get a "Challenge Verification Error" is there any way to fix this? I have tried logging out and relogging back in, fixing the game files and reinstalling the entire game

my t4 waw thing won't start it just stops running when I press play and I tried everything in the faq. it only happens for waw and iw5 and T6 work just fine. I can start the game in LAN mode but i cant play in multiplayer, I've tried the steam copy and the torrented one from the website, please help me as I cant find an answer.