valid_hostname: misplaced delimiter

==== Required information ====
- iRedMail version: 0.8.6
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): mysql
- Linux/BSD distribution name and version: Debian Wheezy 64bit
- Related log if you're reporting an issue: - no log -
====

Hello,

I have a little issue: in my /var/log/mail.log I see this message:

postfix/smtpd[9986]: warning: valid_hostname: misplaced delimiter: .

I checked in my main.cf configuration for hostname value and it's right (without the final dot)
Also /etc/hosts and /etc/hostnames looks good.

Any suggestion about it?

Thanks.