[Cil]

This means that either you changed your username to your account and your client was still running with your old username which means you just need to restart your game/launcher with the correct username, or your account was hacked and someone else has changed your username for you. If you hadn't changed your name, and your account name changed out of the blue, I highly recommend you try to secure your account as soon as possible. The authentication servers for minecraft also could be down though and thats why its displaying this.