Process smtpmail not running

[Announcements and discussions for GNUS, the GNU Emacs Usenet newsreader (in English)]

Hello,

I keep running into a problem wherein I can receive mail without issue,
but attempting to send it results in a long delay returning the error
"Process smtpmail not running". The result is that I cannot send mail.
Restarting Gnus does not seem to help. 

I am using the following to send mail:

(setq gnus-posting-styles
      '(("Countermail:*"
         (x-identity "Countermail")
         (address "x...@countermail.com")
         (reply-to "x...@countermail.com")
         ("X-Message-SMTP-Method" "smtp imap1.countermail.com 465")
;;       (eval (setq mml2015-signers '("x...@countermail.com")))
         (body "\nThanks, xx\n"))

etc for multiple accounts. Thanks in advance for any pointers. 

Aric