gnus unable to login to gmail intermittently

[Vivishek Sudhir <vivishek.sudhir@gmail.com>]

Hi,

I've been using gnus to fetch/reply-to emails on my gmail via gnus' in-built nniamp backend. The minimal working configuration (in my init.el) is as follows:

(use-package gnus
    :config
    (require 'nnir) ; for searching through imap

    (require 'epa-file) ; to be able to code/decode gpg files in emacs
    (epa-file-enable)
    (setq epa-pinentry-mode 'loopback
	     epa-file-cache-passphrase-for-symmetric-encryption t)

    (require 'auth-source) ; setup gpg file access
    (setq auth-sources '((:source "./authinfo.gpg"))) ; this is where to find the login details

    ; set gmail as the primary source of incoming mail
    (setq gnus-select-method
	  '(nnimap "gmail"
		   (nnimap-address "imap.gmail.com")
		   (nnimap-server-port 993)
		   (nnimap-stream ssl)
		   (nnir-search-engine imap)
		   )
	  ; ensure gnus doesnt ignore gmail folders
	  gnus-ignored-newsgroups "^to\\.\\|^[0-9. ]+\\( \\|$\\)\\|^[\”]\”[#’()]"
	  ; mark all sent messages as read
	  gnus-gcc-mark-as-read t 
	  )

    ; configure sending email via gmail smtp, with starttls encryption
    (setq message-send-mail-function 'smtpmail-send-it
	  smtpmail-starttls-credentials '(("smtp.gmail.com" 587 nil nil))
	  smtpmail-auth-credentials '(("smtp.gmail.com" 587 "myemail@gmail.com" nil))
	  smtpmail-default-smtp-server "smtp.gmail.com"
	  smtpmail-smtp-server "smtp.gmail.com"
	  smtpmail-smtp-service 587
	  starttls-use-gnutls t)

      ; cache emails
    (setq message-directory "~/gmail"
	  gnus-use-cache t
	  gnus-cache-directory "~/gmail/cache"
	  gnus-cache-enter-articles '(ticked dormant read unread)
	  gnus-cache-remove-articles nil
	  gnus-cacheable-groups "^nnimap"
	  gnus-keep-backlog 200
	  )

    ; set gnus parameters
    (setq gnus-parameters
      '((".*"
	 (gnus-use-scoring nil)
	 (expiry-wait . 2)
	 (display . all)
	 )))
    ; retrieve 100 newest messages from all groups by default
    ; (setq gnus-parameter-large-newsgroup-initial-alist ((".*" . 100)))
    (setq gnus-large-newsgroup 100)
  )

There is also some buffer formatting settings I've omitted in the above. 

Essentially, the file authinfo.gpg contains my login credentials for gmail's imap and smtp servers, which is read by gnus to log in to fetch/reply-to emails. 

The problem is that *sometimes* when I start gnus, things work perfectly; but about 3 out of 5 times, it would get stuck and show something like "IMAP user at gmail (default <myemail>):" on the minibuffer, and if I do RET, it would ask for my password. It seems that on these occasions, gnus doesn't read the authinfo.gpg file, and falls back to asking me for the login credentials.

Why is this happening, and how can this be solved?

Thanks.