I've used Gnus on the then-current Debian Stable for years.  As of a week
or so ago, it intermittently (over half the time) fails to get or send
email.

When I press 3 g, I get in the minibuffer:

Mail source (pop :server pop.gmail.com :port 995 :user myname@gmail.com
:password ******** :stream ssl) error (POP SSL connexion failed).
 Continue? (yes or no)

The *Messages* buffer shows

nnml: Reading incoming mail from pop...
Opening TLS connection to `pop.gmail.com'...
Opening TLS connection with `gnutls-cli -p 995 pop.gmail.com'...done
Opening TLS connection to `pop.gmail.com'...done
byte-code: Cannot get new mail

If I try to send an email, I get

Sending...
Sending via mail...
Opening TLS connection to `pop.gmail.com'...
Opening TLS connection with `gnutls-cli -p 995 pop.gmail.com'...done
Opening TLS connection to `pop.gmail.com'...done
byte-code: POP SSL connexion failed

That seems odd, as my .emacs shows a line starting

(smtpmail-auth-credentials (quote (("smtp.gmail.com" 587 ...

Has anyone seen this?  Do you have a fix?  Is there an easy way to get more
information about what's happening?

https://superuser.com/questions/243133/intermittent-pop3-errors-re-authentication-failure
and

Thanks,

Bill