Can't access the gnu.* hierarchy using Gnus

[Joseph Fineman]

I use Gnus 5.13 to read newsgroups (as well as mail).  I have
recently encountered a frustration with regard to certain
newsgroups -- in particular, those in the gnu.* hierarchy.  I am
subscribed to them, but they do not show up in the *Group* buffer.
When I bring them up by hitting L, they all show 0 for the number of
postings, and when I call them up, they omit all recent postings.  In
particular, gnu.emacs.gnus shows nothing since 24 September 2016, tho
Google Groups (may its name be blotted out!) reveals a dozen more
recent postings, the latest on 8 January 2017.  Gnus seemed to accept
a posting by me, but it never appeared, there or on Google Groups.

What am I doing wrong?
-- 
---  Joe Fineman    joe_f@verizon.net

||:  It's no disgrace to be poor, but it might as well be.  :||