dovecot - Jul 2016 - authentication failed: Connection lost to authentication server

Dear all,

I got error "authentication failed: Connection lost to authentication
server", i turned on debug mode in Postfix/Dovecot, but this is the error i
can get.

All other errors point to sasl auth failure, what does "connection lost to
authentication server" means? How can i exactly know what the problem is
and how to fix it?

Here's my Dovecot/Postfix configuration, with Active Directory integration.

- dovecot.conf: http://pastebin.com/7T05kvmH
- dovecot-ldap.conf: http://pastebin.com/DtkAg01v
- Postfix main.cf: http://pastebin.com/Z9Wihmvr

Dovecot/Postfix and AD are running in the same network (192.168.10.X), no
firewall between them.

Thanks for your help. :)