If you try to run the game from shortcut that is created during W2 installation, you always get this error and your only option is to restart the game using battle net app (even though my battlenet app is already running, you just need to click PLAY in launcher)
“Lost connection to Battle.net. Please login to Battle.net and restart the client”
i have the same issue!
It’s a known issue. The only solution we have is to launch from the battle.net client. If you don’t need multiplayer, you can modify the shortcut and pass these additional arguments “tigerlily orc1” which will cause the game to load into the 1st orc campaign, bypassing the connection to battle.net, then in-game you can exit to menu. But again note that multiplayer won’t work, you will not see any hosted games.