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安装成功后，只能发邮件，不能收邮件，下面是dovecot日志，imap不能连接

dovecot: Jan 21 12:29:19 Info: imap-login: Login: user=<www@iredmail.org>, method=PLAIN, rip=127.0.0.1, lip=127.0.0.1, secured
dovecot: Jan 21 12:29:19 Info: IMAP(www@iredmail.org): Disconnected: Logged out bytes=263/486
dovecot: Jan 21 12:29:19 Info: imap-login: Login: user=<www@iredmail.org>, method=PLAIN, rip=127.0.0.1, lip=127.0.0.1, secured
dovecot: Jan 21 12:29:19 Info: IMAP(www@iredmail.org): Disconnected: Logged out bytes=317/5291
dovecot: Jan 21 12:29:22 Info: imap-login: Login: user=<www@iredmail.org>, method=PLAIN, rip=127.0.0.1, lip=127.0.0.1, secured
dovecot: Jan 21 12:29:23 Info: IMAP(www@iredmail.org): Disconnected: Logged out bytes=254/1891
dovecot: Jan 21 12:30:22 Info: imap-login: Login: user=<www@iredmail.org>, method=PLAIN, rip=127.0.0.1, lip=127.0.0.1, secured
dovecot: Jan 21 12:30:23 Info: IMAP(www@iredmail.org): Disconnected: Logged out bytes=531/2602
dovecot: Jan 21 12:30:58 Info: imap-login: Login: user=<www@iredmail.org>, method=PLAIN, rip=127.0.0.1, lip=127.0.0.1, secured
dovecot: Jan 21 12:30:58 Info: IMAP(www@iredmail.org): Disconnected: Logged out bytes=300/5626
dovecot: Jan 21 12:31:02 Info: imap-login: Login: user=<www@iredmail.org>, method=PLAIN, rip=127.0.0.1, lip=127.0.0.1, secured
dovecot: Jan 21 12:31:02 Info: IMAP(www@iredmail.org): Disconnected: Logged out bytes=25/181
dovecot: Jan 21 12:31:14 Info: imap-login: Login: user=<www@iredmail.org>, method=PLAIN, rip=127.0.0.1, lip=127.0.0.1, secured
dovecot: Jan 21 12:31:14 Info: IMAP(www@iredmail.org): Disconnected: Logged out bytes=25/181
dovecot: Jan 21 12:31:20 Info: imap-login: Login: user=<www@iredmail.org>, method=PLAIN, rip=127.0.0.1, lip=127.0.0.1, secured
dovecot: Jan 21 12:31:20 Info: IMAP(www@iredmail.org): Disconnected: Logged out bytes=25/181
dovecot: Jan 21 12:37:14 Info: imap-login: Login: user=<www@iredmail.org>, method=PLAIN, rip=127.0.0.1, lip=127.0.0.1, secured
dovecot: Jan 21 12:37:14 Info: IMAP(www@iredmail.org): Disconnected: Logged out bytes=323/6296
dovecot: Jan 21 12:37:16 Info: imap-login: Login: user=<www@iredmail.org>, method=PLAIN, rip=127.0.0.1, lip=127.0.0.1, secured
dovecot: Jan 21 12:37:16 Info: IMAP(www@iredmail.org): Disconnected: Logged out bytes=254/1898
dovecot: Jan 21 12:37:35 Info: imap-login: Login: user=<www@iredmail.org>, method=PLAIN, rip=127.0.0.1, lip=127.0.0.1, secured
dovecot: Jan 21 12:37:35 Info: IMAP(www@iredmail.org): Disconnected: Logged out bytes=343/1177
dovecot: Jan 21 12:37:45 Info: imap-login: Login: user=<www@iredmail.org>, method=PLAIN, rip=127.0.0.1, lip=127.0.0.1, secured
dovecot: Jan 21 12:37:45 Info: IMAP(www@iredmail.org): Disconnected: Logged out bytes=343/9333
dovecot: Jan 21 12:37:55 Info: imap-login: Login: user=<www@iredmail.org>, method=PLAIN, rip=127.0.0.1, lip=127.0.0.1, secured
dovecot: Jan 21 12:37:55 Info: IMAP(www@iredmail.org): Disconnected: Logged out bytes=340/1190