This post and this one on the BioWare Social Network have complaints from players encountering errors when attempting to play Mass Effect 3 multiplayer. Most of this seems to involve being told they require an "online pass," which does not exist for the PC version of the game, as it is used as a way of combating used console game sales. There are also indications that those who own the From Ashes DLC are not even able to play the game in singleplayer mode. There are posts from players claiming they've been told BioWare is working on the problem. Thanks Mark.