Please make sure you're not in offline mode in steam. And you may want to verify your local file cache. Beyond that, are you getting the steam overlay in game? Be sure to launch the game from within steam. You should see ai war noting you are logged in as your steam username in the upper left when you're successfully connected.
Hope that helps!
Steam online.
"Verify integrity of game cache" says all fine.
Overlay by Shift+Tab present.
Game launched by steams "Play" button.
Upper left of screen: "Game Version 6.009" only. So - for some reason I unlogged.
Another strange steam behavior: I try delete game and reinstall it from steam. After reinstall - game cant launched by missing exec. I watched to it folder - and there are only 4 expansions folders present, without main game. So steam dont want install main game files and dont want see them. Because "verify integrity" not found any errors. I download installer from this site and install it to the same steam folder - game is works now. But achievements dont works before delete and after reinstall same.