This message is also kind of generic and doesn't really mean the server is full. It's more likely the connection is busy or you are being denied access.
Did you recently purchase a new First Class Ticket? If so re-enter your login information (same username and password you use for the forum and your Planet Auran account) and try again.
The other issue could be your Internet connection is busy. Try connecting at another time.
There are possibly other reasons. I'm sure others here will pipe up too and have some more suggestions and things to try.
I had that for a couple of days it usually happens if your download list is full on CMP best thing to do is make a note of what you are downloading by copying and pasting the titles onto notepad and try again but one at a time it takes longer but thats the trouble with having no FCT but you get used to it, CMP downloading speeds is sometimes quicker than the normal downloading programs.