==== Required information ====
- iRedMail version (check /etc/iredmail-release):  0.9.6 OPENLDAP edition.
- Linux/BSD distribution name and version: Debain Jessie
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): LDAP - Active Directory
- Web server (Apache or Nginx): NGINX
- Manage mail accounts with iRedAdmin-Pro? NO
- Related log if you're reporting an issue:
====

mail.log

Apr 21 09:41:01 ostala postfix/cleanup[1423]: A38F43C422AE: message-id=<20170421144101.50B953C422E1@ostala.doucl.com>
Apr 21 09:41:01 ostala postfix/10025/smtpd[1430]: disconnect from localhost.localdomain[127.0.0.1]
Apr 21 09:41:01 ostala postfix/qmgr[1387]: A38F43C422AE: from=<sogo@ostala.doucl.com>, size=1437, nrcpt=1 (queue active)
Apr 21 09:41:01 ostala amavis[1409]: (01409-03) Passed CLEAN {RelayedInbound}, [127.0.0.1] <sogo@ostala.doucl.com> -> <sogo@ostala.doucl.com>, Message-ID: <20170421144101.50B953C422E1@ostala.doucl.com>, mail_id: Jo6XfsipcGYK, Hits: 0, size: 949, queued_as: A38F43C422AE, 174 ms, Tests: [NO_RELAYS=-0.001,TVD_SPACE_RATIO=0.001]
Apr 21 09:41:01 ostala postfix/smtp-amavis/smtp[1792]: 50B953C422E1: to=<sogo@ostala.doucl.com>, relay=127.0.0.1[127.0.0.1]:10024, delay=0.36, delays=0.18/0/0/0.18, dsn=2.0.0, status=sent (250 2.0.0 from MTA(smtp:[127.0.0.1]:10025): 250 2.0.0 Ok: queued as A38F43C422AE)
Apr 21 09:41:01 ostala postfix/qmgr[1387]: 50B953C422E1: removed
Apr 21 09:41:01 ostala postfix/cleanup[1794]: A46943C422E4: message-id=<20170421144101.50B953C422E1@ostala.doucl.com>
Apr 21 09:41:01 ostala postfix/local[1431]: A38F43C422AE: to=<sogo@ostala.doucl.com>, relay=local, delay=0.1, delays=0/0/0/0.1, dsn=2.0.0, status=sent (forwarded as A46943C422E4)
Apr 21 09:41:01 ostala postfix/qmgr[1387]: A46943C422E4: from=<sogo@ostala.doucl.com>, size=1572, nrcpt=1 (queue active)
Apr 21 09:41:01 ostala postfix/qmgr[1387]: A38F43C422AE: removed

dovecot.log

Apr 21 09:40:37 ostala dovecot: lda: Error: userdb lookup(postmaster@doucl.com): Connecting timed out
Apr 21 09:40:37 ostala dovecot: lda: Fatal: Internal error occurred. Refer to server log for more information.
Apr 21 09:40:39 ostala dovecot: master: Warning: Killed with signal 15 (by pid=1 uid=0 code=kill)
Apr 21 09:40:39 ostala dovecot: config: Warning: Killed with signal 15 (by pid=1 uid=0 code=kill)
Apr 21 09:40:39 ostala dovecot: anvil: Warning: Killed with signal 15 (by pid=1 uid=0 code=kill)
Apr 21 09:40:39 ostala dovecot: log: Warning: Killed with signal 15 (by pid=1 uid=0 code=kill)
Apr 21 09:41:37 ostala dovecot: lda: Error: userdb lookup(postmaster@doucl.com): Connecting timed out
Apr 21 09:41:37 ostala dovecot: lda: Fatal: Internal error occurred. Refer to server log for more information.
Apr 21 09:41:41 ostala dovecot: lda: Error: userdb lookup(user@doucl.com): Connecting timed out
Apr 21 09:41:41 ostala dovecot: lda: Fatal: Internal error occurred. Refer to server log for more information.

telnet localhost 143

root@ostala:/etc/dovecot# telnet localhost 143
Trying ::1...
Connected to localhost.localdomain.
Escape character is '^]'.
* OK [CAPABILITY IMAP4rev1 LITERAL+ SASL-IR LOGIN-REFERRALS ID ENABLE IDLE STARTTLS AUTH=PLAIN AUTH=LOGIN] Dovecot ready.
. login user@doucl.com ************
* OK Waiting for authentication process to respond..

.login user@doucl.com ************
* OK Waiting for authentication process to respond..

dovecot-imap.log

Apr 21 09:11:30 ostala dovecot: imap-login: Disconnected: Inactivity during authentication (disconnected while authenticating, waited 170 secs): user=<>, method=PLAIN, rip=::1, lip=::1, secured, session=<kypqy61NjAAAAAAAAAAAAAAAAAAAAAAB>
Apr 21 09:11:42 ostala dovecot: imap-login: Error: Timeout waiting for handshake from auth server. my pid=2217, input bytes=0
Apr 21 09:11:42 ostala dovecot: imap-login: Disconnected: Auth process broken (disconnected before auth was ready, waited 30 secs): user=<>, rip=::1, lip=::1, secured, session=<oxU71q1NCAAAAAAAAAAAAAAAAAAAAAAB>
Apr 21 09:25:46 ostala dovecot: imap-login: Warning: Auth process not responding, delayed sending initial response (greeting): user=<>, rip=::1, lip=::1, secured, session=<4NiKCK5NkgAAAAAAAAAAAAAAAAAAAAAB>
Apr 21 09:26:06 ostala dovecot: imap-login: Error: Timeout waiting for handshake from auth server. my pid=1440, input bytes=0
Apr 21 09:26:06 ostala dovecot: imap-login: Disconnected: Auth process broken (disconnected before auth was ready, waited 30 secs): user=<>, rip=::1, lip=::1, secured, session=<4NiKCK5NkgAAAAAAAAAAAAAAAAAAAAAB>
Apr 21 09:33:13 ostala dovecot: imap-login: Error: Timeout waiting for handshake from auth server. my pid=1647, input bytes=0
Apr 21 09:33:13 ostala dovecot: imap-login: Disconnected: Auth process broken (disconnected before auth was ready, waited 30 secs): user=<>, rip=::1, lip=::1, secured, session=<S6QqI65NLgAAAAAAAAAAAAAAAAAAAAAB>