Intermittent problem with gnus and Gmail POP3

[Bill Harris]

Starting about a year or more ago, I've had increasing intermittent
problems with accessing my gmail account with gnus via POP3
(https://osdir.com/ml/info-gnus-english-gnu/2014-07/msg00049.html).

Does anyone have any suggestions?

----------------------------------------------------------------------

My intent:

  Read mail via POP3 into gnus using a secure protocol, leaving
  downloaded mail on gmail, too.

  Send email via SMTP on gmail using a secure protocol.

----------------------------------------------------------------------

My problem: when I'm downloading, perhaps 90% of the time, I get this
message in the mini-buffer:

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

If I don't get that message, it works just fine.

When I'm sending a message, about 90% of the time, I get 

,----
| POP SSL connexion failed
`----

If I don't get that message, it works just fine.  It's inconsistent:
sometimes it works fine for quite a while, and sometimes it doesn't for
quite a while.

----------------------------------------------------------------------

My local POP3 configuration:

,----[ set via customize in the Mail Source group ]
| mail-sources's value is
| ((pop :server "pop.gmail.com" :port 995 :user "****@gmail.com" :password 
"***" :stream ssl))
`----

That seems consistent with
https://support.google.com/mail/troubleshooter/6323470?hl=en&ref_topic=3397961#ts=1665162
and http://www.emacswiki.org/emacs/GnusGmail#toc7.  

My gmail POP3 configuration:

- Forwarding: Disable forwarding
- Status: POP is enabled for all mail ....
- When messages are accessed with POP mark Gmail's copy as read
- Status: IMAP is disabled.
- Access for less secure apps (I've tried 'Turn off' and 'Turn on', to
  no avail)

The Pop3 group has more set:

,----
| '(pop3-leave-mail-on-server nil)
`----

I don't want that, as I said, but that doesn't seem to create a problem,
since I've told gmail simply to mark downloaded email as read, not to
delete it.  

I also can't imagine that this affects my ability to download email, so
I'm leaving it alone for now.  It sounds like I want to change that
later, though, just for safety.

My customize section of my .emacs has

,----
| '(read-mail-command (quote gnus))
`----

----------------------------------------------------------------------

My local SMTP configuration:

,----[ in my .gnus ]
| (require 'tls)
`----

,----[ in the customize section of my .emacs ]
| '(smtpmail-auth-credentials (quote (("smtp.gmail.com" 587 
"********@gmail.com" "********"))))
| '(smtpmail-default-smtp-server "smtp.gmail.com")
| '(smtpmail-smtp-server "smtp.gmail.com")
| '(smtpmail-smtp-service 587)
| '(smtpmail-starttls-credentials (quote (("smtp.gmail.com" 587 "" ""))))
`----

That seems consistent with http://www.emacswiki.org/emacs/GnusGmail.  

----------------------------------------------------------------------

My environment:

,----
| Debian 7.9
| Gnus v5.13
| GNU Emacs 23.4.1
`----

Does anyone see anything I'm missing?

Thanks,

Bill
-- 
Bill Harris