==== Required information ====
- iRedMail version (check /etc/iredmail-release):
- Linux/BSD distribution name and version: ubuntu server 16.04
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): mysql
- Web server (Apache or Nginx): apache
- Manage mail accounts with iRedAdmin-Pro? no
- Related log if you're reporting an issue:
====
Hi everyone!
I have a strange problem..
Sometimes when i try to connect to my server with outlook i get an error: server not available.
So i try to connect to the mail with roundcube using a webbrowser with www.mydomain.com and again it is not reacheable.

While if i connect using my internal ip it  Works. And if i try from another connection like my iPhone via 3G or another location i can Reach it
This problem persists for about 12 hours then magically comes back normal.
What could it be?
Thank you

Ale