Currently there is a bug that will not let you reconnect after disconnecting, I don't know if it only works sometimes or not but everyone has said they havn't been able to reconnect. So I may have found a way to fix but I can't guarantee it works, couple times I tried this it didn't work and still gave the error but I managed to reconnect most of the time doing this.
1. DO NOT click "yes" or "no" when asked to reconnect.
2. Minimize guild wars, press and hold "Ctrl" and "Alt" and tap "Delete," this will open your Task Manager. Depending on your operating system you need to find the Gw.exe process in the "Processes" tab. Find it, select it, and click "End Task" or "End Process." This will close Guild Wars improperly.
3. Open Guild Wars again like normal, sign in making sure in the "Security Question" to type the name of the character you lost connection on. If you don't type the char name u lost connection on it will not ask you to reconnect.