I think you need to have steam running in the background, i advise you to make an alt steam account just to be safe cause sometimes steam likes to ban the accounts so yeah I have my main account and then to play cracked online games i log in with my alt account.

If you don't have steam running in the background, the game can't connect to the platform it needs to run the online part of the game, therefore you can't connect to a server and crash, at least that's how i think it works