gnus-summary-insert-new-articles not working nnimap emacs 25.1.50.2

[George Moutsopoulos]

Hi,
I access gmail and yahoo imap mail directly from gnus using nnimap. A problem 
I face is that /N in summary buffer does not bring in any new mail.

A minimal configuration I have tries is
~/.emacs.d/init.el
(setq
 gnus-directory "~/.emacs.d/gnus/" ;; most vars initiated from 
 gnus-home-directory "~/.emacs.d/gnus/" ;; all vars initiated from
 gnus-init-file "~/.emacs.d/lisp/gnusrc.el")

~/.emacs.d/lisp/gnusrc.el
(setq gnus-select-method '(nnimap "gmail"
                      (nnimap-address "imap.gmail.com")
                      (nnimap-server-port 993)
                      (nnimap-stream ssl)
                      ))

emacs version 25.1.50.2, gnus v 5.13

I also have this question. I set (display . all) in gnus-parameters but I want 
to only see unread messages when I am unplugged in the gnus-agent. Is it 
possible, rather than seeing [undownloaded messages]?

Thanks