Emacs Gnus open error?

[Shenli]

Hi all,

I have used Emacs for several month, love it and try to use it as a
mail/news
client.

After set gnus-select-method(is it the minimal setting option?) by
custom-set-variables
'(gnus-select-method (quote (nntp "gnu.emacs.bug")))

I try to link to the news server, but Emacs give out error as below.

"Unable to open server nntp+gnu.emacs.bug, go offline?
nntp (gnu.emacs.bug) open error: '', Continue?"

My environment is WinXP and Emacs23.1.
Any suggestion is welcome!

Thanks,
Shenli