我正在配置 Gnus 以通过 IMAP 从我的 Gmail 帐户检索电子邮件。我已按照以下建议进行操作：https://www.emacswiki.org/emacs/GnusGmail，但是我在启动时不断收到 Gnus 的错误：
Opening connection to imap.gmail.com via tls...
nnimap (gmail) open error: 'NO (ALERT) Please log in via your web browser:
https://support.google.com/mail/accounts/answer/78754 (Failure)'. Continue? (y
or n) y
Saving file /home/mark/.newsrc-dribble...
Wrote /home/mark/.newsrc-dribble [2 times]
Gnus auto-save file exists. Do you want to read it? (y or n) y
Opening nnimap server on gmail...
Server nnimap+gmail previously determined to be down; not retrying
Opening nnimap server on gmail...failed: NO (ALERT) Please log in via your web
browser: https://support.google.com/mail/accounts/answer/78754 (Failure)
Checking new news...
Reading active file from gmail via nnimap...
Opening nnimap server on gmail...
Server nnimap+gmail previously determined to be down; not retrying
Opening nnimap server on gmail...failed: NO (ALERT) Please log in via your web
browser: https://support.google.com/mail/accounts/answer/78754 (Failure)
Reading active file via nndraft...done
Checking new news...done
No news is good news
Warning: Opening nnimap server on gmail...failed: NO (ALERT) Please log in via
your web browser: https://support.google.com/mail/accounts/answer/78754
(Failure); Server nnimap+gmail previously determined to be down; not retry\
ing; Opening nnimap server on gmail...failed: NO (ALERT) Please log in via your
web browser: https://support.google.com/mail/accounts/answer/78754 (Failure);
Server nnimap+gmail previously determined to be down; not retrying
gnus-group-read-group: No group on current line
我已经安装了 GnuTLS，并且 gnutls-cli 似乎可以与 imap.gmail.com:993 配合使用，我得到了“OK Gimap ready for request”的消息。
这是我的〜/ .gnus：
;;
(setq gnus-select-method
'(nnimap "gmail"
(nnimap-address "imap.gmail.com")
(nnimap-server-port 993)
(nnimap-stream ssl)
(nnir-search-engine imap)
(nnimap-authinfo-file "~/.authinfo")))
(setq smtpmail-smtp-service 587
gnus-ignored-newsgroups "^to\\.\\|^[0-9. ]+\\( \\|$\\)\\|^[\"]\"[#'()]")
我的 ~/.authinfo 如下所示：
machine imap.gmail.com login [email protected] password my_password port 993
machine smtp.gmail.com login [email protected] password my_password port 587
可能是什么问题呢？