Session lost

[Iɴтoхιcαтιoɴ]

Hey, i installed Arma 2, Arma 2 OE and Arma 2 Dayz Mod. Its a new clean install. I also downloaded the Arma 2 Launcher. Whenever i try to join a server, it shows me "Session lost". I cant join on any server. I started all the games, i deleted and reinstalled BattleEye, i verified the game files. I dont know what else to do. Any suggestions? Thanks