Windows email error

[Raymond]

I have add following into my emacs. Why I can't use smtp mail still?
When I send email. The error message is "SMTP protocol error!".

;; If you use the default mail user agent.
(setq send-mail-function 'smtpmail-send-it)
;; If you use Message or Gnus.
(setq message-send-mail-function 'smtpmail-send-it)

(setq user-full-name "Raymond Shen")
(setq user-mail-address "shen_yong_cn@163.com")

(setq smtpmail-smtp-server "smtp.163.com")
(setq smtpmail-auth-credentials
      '(("smtp.163.com" 25 "shen_yong_cn" "passwd")))

(setenv "MAILHOST" "pop3.163.com")
(setq rmail-primary-inbox-list
    '("po:shen_yong_cn") rmail-pop-password-required t)