Anytime you lose connection with the game server you will be automatically logged out and you will see this screen. The loss of connection can occur on our network, your network or anywhere in between so keep that in mind when attempting to correct the problem.
If you find yourself at this screen hit ESC and attempt to log back in. A hiccup anywhere down the line can knock you offline for a minute and you will find that you can get back in the game immediately. At this point if you cannot log back in, exit from DAoC and attempt to access the Internet externally. If you cannot access the Internet then you should troubleshoot your Internet connection. If you are still online but not able to play DAoC you may be trying to log in during patch time.