I recently set up two xbox live accounts for my kids' new 360 console. Each of them are able to sign in to xbox live when they're playing a game by themselves. But when they both want to sign in and play a game together, the first account will sign in fine, but the second will get an error message that they can't be signed in right now and to try again later (error code 80070057). I've been troubleshooting for a while today and can't figure out the problem. Any advice for this xbox newbie is appreciated! Thanks!