I know Wurst can fix that, happens all the time. Usually it happens when you change the way you connect to server: (form the list of all servers, from your favorites, via /connect IP:port, /connect dswp.de:port, through an external server browser, etc.). It also happened to everyone then the server changes IP.
If you think it's urgent, maybe SavRoX can help you, try finding him in
IRC.