linux sendmail 服务器建立以后。使用telnet能够登录，但是outlook不能登录

outlook： 登录邮件服务器时出错。“用户名”被拒绝。 帐户: 'mail.qiaorong.com', 服务器: 'mail.qiaorong.com', 协议: POP3, 服务器响应: '-ERR Plaintext authentication disallowed on non-secure (SSL/TLS) connections.', 端口: 110, 安全(SSL): 否, 服务器错误: 0x800CCC90, 错误号: 0x800CCC91
/var/log/maillog 日志如下：
Oct 28 08:52:54 qiaorong dovecot: imap(qiaorong): Error: user qiaorong: Initialization failed: mail_location not set and autodetection failed: Mail storage autodetection failed with home=/home/qiaorong
Oct 28 08:52:54 qiaorong dovecot: imap(qiaorong): Error: Invalid user settings. Refer to server log for more information.
Oct 28 08:54:23 qiaorong dovecot: master: Warning: Killed with signal 15 (by pid=1455 uid=0 code=kill)
Oct 28 08:54:24 qiaorong dovecot: master: Dovecot v2.0.beta6 (3156315704ef) starting up (core dumps disabled)
Oct 28 08:57:43 qiaorong dovecot: imap-login: Disconnected: Inactivity (tried to use disabled plaintext auth): rip=192.168.1.21, lip=192.168.1.16, mpid=0
Oct 28 09:00:33 qiaorong dovecot: imap-login: Disconnected (no auth attempts): rip=192.168.1.21, lip=192.168.1.16, mpid=0
Oct 28 09:27:24 qiaorong dovecot: pop3-login: Disconnected (tried to use disabled plaintext auth): rip=192.168.1.21, lip=192.168.1.16, mpid=0
Oct 28 09:27:26 qiaorong dovecot: pop3-login: Disconnected (tried to use disabled plaintext auth): rip=192.168.1.21, lip=192.168.1.16, mpid=0

解决方法:
 

唉。整了这么多天终于自己整出来了，欣欣然。这个问题主要原因是mail_location not set and autodetection failed 两个问题
关于第一个mail_location ，在/etc/dovecot/conf.d目录下有一个10-mail.conf的文件。内容如下：
#   mail_location = maildir:~/Maildir
    mail_location = mbox:~/mail:INBOX=/var/mail/%u
#   mail_location = mbox:/var/mail/%d/%1n/%n:INDEX=/var/indexes/%d/%1n/%n
取消注释
关于第二个问题。还是dovecot的问题，找到/etc/dovecot/dovecot.conf 文档，编辑里面的内容
protocols = imap pop3 lmtp
disable_plaintext_auth=no
ssl_disable = no
取消注释，并添加你的文件中或许没有的内容。