Navigator won't let you read news articles

There are two reasons why Netscape Navigator might not let you read news
articles from your news server (and give you errors when you try to):
One is that your news server possibly isn't up to NNTP standards, and
can't retrieve articles by their standard NNTP message ID.  (Some older
news servers can only retrieve articles if you provide the local article
number.)
The other is that the history database on your news server might be
corrupt and needs to be rebuilt.
If you are having trouble reading news from Netscape Navigator, then
investigate these possibilities with your local system administrators.