After following several guides i faced an issue with the mail reporting.
Since sendmail provided by zimbra doesn’t work with the same parameters like the default sendmail i modified the mail function of Fail2Ban.
– I have enabled only notifications for Webmail/Webadmin login attemps
For Red Hat /CentOS you will need EPEL Repo
rpm -Uvh http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm