I konw that this is an older Thread but
since 3 Days I can´t join any Servers, always I get a Blank Lobby Screen, if I press Ok, the Loading Screen is showing up but nothing happend and than I get kicked back to the Serverlist. I was trying to join a lot of different Servers but always the same. The Ping to the Servers I connect is between 15 and 90. Than i was trying to re-install ArmA III/ Mods / Steam / BE, but nothing happend. I was checking AV/Firewall, but after the same problem there. I didn´t find anything in other Forums that helps me. Also I start Steam and ArmA as Administrator and i clear the gamecache.
I upgrade also win8 to win10 but every time the role assignment is blank.