I've had a problem for several months where I can't buy items from the in-game store as when you click on purchase the window does not advance. Research seems to indicate this is a problem with Steam overlays but these are enabled globally and also at the game level. My work around has been to purchase via the web store but this also no longer works. I can use my Steam credentials to logon to the store and select items but when I click on purchase a second window opens prompting another logon via Steam, after clicking on logon the timer spins around for a couple of minutes until I get a 502 bad gateway error. Any ideas ?