For those who see the following error during installation
You can ignore the error during installation and solve the issue afterwards, see here Port conflict detected: 25 (zimbra-mta) | awesomeITCode:Checking for port conflicts Port conflict detected: 25 (zimbra-mta) Port conflicts detected! - Any key to continue Setting defaults from ldap...done.
Just in case the website goes offline:
Code:apt-get remove exim4 --purge update-rc.d -f exim4 remove