Cannot connect to nntp.gmane.org news.gmane.org nntp.aioe.org and most of the nntp servers

[bullone]

After  a long time struggling with   gnus  to integrate with offlineimap and 
dovecot, gnus could read mails from the integration.

During the  integrating process, at first  my dovecot was not configured well
(I lost the  "LAYOUT=fs" of "mail_location = maildir:%h/Maildir:LAYOUT=fs"), 
all my INBOXes of several gmail accounts mixed in one INBOX ,and some contents 
of the messages did not correspond to titles in the summary buffer.

At that time I blindly did gnus-group-clear-data-on-native-groups a lot of 
times.
I didn't know whether this action would ruin  my .newsrc.eld or not.

Now I could see the groups of nnimap methods which  connect to my local dovecot 
maildir(although there are still something I cannot explain: 
like---each nnimap method contains groups which should belong to other methods 
and I cannot open these kind of groups).

What's worse is  I cannot open any NNTP servers anymore.

I've asked on the #gnus, and googled but still have no ideas about it .

when I open gnus, the error as below appears:
>>> (error nntp.gmane.org/nntp 未知的名稱或服務)
nntp (nntp.gmane.org) open error: '>>> (error nntp.gmane.org/nntp 未知的名稱或服務)'.  
Continue? (y or n)  n
Couldn't open server on nntp.gmane.org
Quit [3 times]

and I have tried as batin suggested(batin:Thank you :-)) :
1.C-u M-x gnus
2. restart emacs with "-q" 
3. rename .newsrc and .newsrc.eld
but still with no luck...

below is my .gnus:

(require 'pgg)
(setq user-full-name "Frank")
(setq nnrss-use-local t)
(setq imap-shell-program "MAIL=maildir:$HOME/Maildir /usr/lib/dovecot/imap")
(defun my-message-mode-setup ()
   (setq fill-column 72)
   (turn-on-auto-fill))
  (add-hook 'message-mode-hook 'my-message-mode-setup)

(setq message-send-mail-function 'message-send-mail-with-sendmail)
(setq sendmail-program "/usr/bin/msmtp")
(setq gnus-permanently-visible-groups ".*")
(add-hook 'gnus-group-mode-hook 'gnus-topic-mode)
(require 'gnus-switch)



and below is part of my custom-file:
 '(gnus-buttonized-mime-types (quote ("multipart/alternative" 
"multipart/signed")))
 '(gnus-default-charset (quote chinese-iso-8bit))
 '(gnus-group-list-inactive-groups nil)
 '(gnus-group-name-charset-group-alist (quote ((".*" . utf-8) 
("\\\\.com\\\\.cn:" . cn-gb-2312))))
 '(gnus-group-name-charset-method-alist (quote (((nntp "news.newsfan.net") . 
gbk))))
 '(gnus-group-use-permanent-levels t)
 '(gnus-keep-same-level t)
 '(gnus-newsgroup-ignored-charsets (quote (unknown-8bit x-unknown iso-8859-1)))
 '(gnus-notifications-minimum-level 3)
 '(gnus-save-killed-list nil)
 '(gnus-select-method (quote (nntp "news.gmane.org")))
 '(gnus-secondary-select-methods
   (quote
    ((nnimap "kiss"
             (nnimap-address "localhost")
             (nnimap-server-port 993)
             (nnimap-stream shell)
             (nnimap-shell-program "MAIL=maildir:$HOME/Maildir/kiss 
/usr/lib/dovecot/imap")
             (nnimap-authinfo-file "~/.authinfo.gpg"))
     (nnimap "99"
             (nnimap-address "localhost")
             (nnimap-server-port 993)
             (nnimap-stream shell)
             (nnimap-shell-program "MAIL=maildir:$HOME/Maildir/99 
/usr/lib/dovecot/imap")
             (nnimap-authinfo-file "~/.authinfo.gpg"))
     (nnimap "kulug"
             (nnimap-address "localhost")
             (nnimap-server-port 993)
             (nnimap-shell-program "MAIL=maildir:$HOME/Maildir/kulug 
/usr/lib/dovecot/imap")
             (nnimap-stream shell)

Any idea will be appreciate!
Frank