Have you changed your ISP? If not, there may be a different server for broadband access (have a look at your ISP's FAQ help).
If you're not using the ISP's news server, then check your firewall (assuming you have one) to make sure that your news reader can acess the server. If you want to test out your reader, have a google for free servers (read only) and try them - or there is a german site (
http://news.individual.net/)
where you can register for a free newsgroup account (text only) - takes a couple of days to get username and password.