I deleted it and gnus works now. Thank you, guys!

BR,
Vincent Zhang
在 2019年12月28日 +1300 13:52,Lars Ingebrigtsen <larsi@gnus.org>,写道:
Eric Abrahamsen <eric@ericabrahamsen.net> writes:

Vincent Zhang <seagle0128@gmail.com> writes:

Debugger entered--Lisp error: (wrong-type-argument number-or-marker-p nil)
<=(nil 6)
gnus-get-unread-articles(nil nil)
gnus-setup-news(nil nil nil)
#f(compiled-function () #<bytecode 0x1ff08dde5bdd>)()
gnus-1(nil nil nil)
gnus(nil)

This happens when the variable `gnus-group-list-mode' is nil, which it
shouldn't be. Nothing has touched that variable any time recently -- can
you do some poking around and figure out why it's nil?

No, this was due to the recent gnus-start.el changes, and it should now
be fixed on both Emacs 27 and the trunk.

There may be extra nil entries in the start of gnus-newsrc-alist in
.newsrc.eld -- if there are, delete them.

--
(domestic pets only, the antidote for overdose, milk.)
bloggy blog: http://lars.ingebrigtsen.no