It says this when there are 62 players online.
Basically the server it is full. It is natural. Do not worry.
Only Supporting Members will be able to log onto the server straight away because they help pay for it. The rest of us have to keep trying every three seconds or so, to log on.
I think the
TG Admins have not been able to change the wording, hence the confusion.
Keep trying and you will eventually get onto the server.
Keep going, someone will log out but remember the server is full at 62 players because it needs the other two slots to allow the flow of people coming on. The 64th place is never filled or the server would jam up because it need this slot to let people on - and the longest playing 'non-supporting' person is removed, which ensures everyone gets a fair go. Of course if that person is you, you can log back on right away. Remember, you have not been kicked or punished - it's just some computer technical issue about changing the wordage, that's all.
So keep trying to log on - you will!
Hope that helps; it's late so I also hope it was clear.
<edit> I see whilst writing others have shown you the way.