iRedMail is:
1. A ZERO COST, fully fledged, full-featured mail server solution. All components are free and open source software
2. It support unlimited domains and email accounts.
2. SpamAssassin, ClamAV, SPF, DKIM, greylisting, whitelisting, blacklisting.
3. Stores mail accounts in your favourte backend: OpenLDAP, MySQL, MariaDB, PostgreSQL.
4. Supports major Linux distros

You know how difficult is to configure a fully fledged email service you have tried. iRedmail do this heavy part for you. I would recommend this piece of software to everyone. I used to configure email server manually using Postfix, Postfixadmin, MySQL, SpamAssassin, etc. Even though I have done this several times, it needs 2-3 hours for setup. But iRedmail can do all of this and MORE in few minutes, thus saves lot of time.

iRedmail comes with SOGo which provides EAS Activesync support

SOGo is providing the EAS support. If you are getting an error “Unable to connect” on email client do following

1. Check https://hostname/Microsoft-Server-ActiveSync

if it gives 404, issue with SOGo httpd conf
If it gives white page, no problem with conf

SOGo installs Apache config file /etc/httpd/conf.d/SOGo.conf by default, please open it and find below lines:

#ProxyPass /Microsoft-Server-ActiveSync \
# \
# retry=60 connectiontimeout=5 timeout=360

Remove # at the beginning to enable ActiveSync support:
ProxyPass /Microsoft-Server-ActiveSync \ \
retry=60 connectiontimeout=5 timeout=360

Find string yourhostname in the same file, replace all yourhostname by your FQDN server hostname. (Tip: you can get your FQDN hostname with command hostname -f.)

Restart Apache