[root@localhost ~]# telnet mail.izyno.com 110
Trying 192.168.199.133...
Connected to mail.izyno.com.
Escape character is ‘^]‘.
+OK Dovecot ready.
USER test
+OK
PASS test
Connection closed by foreign host.
[root@localhost ~]# vim /etc/dovecot/conf.d/10-mail.conf 
mbox_write_locks = fcntl
mail_location = mbox:~/mail:INBOX=/var/mail/%u
确认以上两项启动root@localhost ~]# service dovecot restart
Stopping Dovecot Imap:                                     [  OK  ]
Starting Dovecot Imap:                                     [  OK  ]
重新连接：
[root@localhost ~]# telnet mail.izyno.com 110
Trying 192.168.199.133...
Connected to mail.izyno.com.
Escape character is ‘^]‘.
+OK Dovecot ready.
USER test
+OK
PASS test
-ERR [IN-USE] Couldn‘t open INBOX: Internal error occurred. Refer to server log for more information. [2016-11-19 14:48:53]
Connection closed by foreign host.
创建INBOX目录
[root@localhost ~]# mkdir -p /home/test/mail/.imap/INBOX
[root@localhost ~]# telnet mail.izyno.com 110
Trying 192.168.199.133...
Connected to mail.izyno.com.
Escape character is ‘^]‘.
+OK Dovecot ready.
user test
+OK
pass test
+OK Logged in.
连接成功 

postfix下dovecot查收邮件连接错误