Same thing happened to me on RC. I did notice that LFS was hidden from my taskbar but was in the backround of my other programs, it had never happened before and was really weird. I had to make someone kick me, and then it'd be fine.
That happens because for some reason server does not report to LFSW that your account has left the server.
I suppose you have to contact the server owner for that - either he kicks your username from server or restarts it,as there are obviously some connection problems.
Get someome to go into the server and kick you out, or the server host will do it remotely. If that doesn't work, like Rony said, the server needs to be reset and rebooted.
It happens when there is a failure/desync in the connection between the server host, LFS hosting system and the user's computer. You physically are booted or out of the server but virtually your account gets stuck in the server.
This is not to be linked with actual disconnection or latency issues direct between the user and the LFS. that just causes your normal DC or JOOS.
This is at least what I know and think is happening. I may be just talking shit lol