Step by step guide the solve problem zimbra some services are not running the following:
To restart and enable cron service the permanently.
service crond restart
chkconfig crond on
Opening rsyslog.conf file and uncomment the following.
vim /etc/rsyslog.conf
Uncomment these two lines
$modload imupd
$UDPServerRun514
To restart and enable rsyslog service the permanently.
service rsyslog restart
chkconfig rsyslog on
To update /etc/rsyslog.conf file.
/opt/zimbra/libexec/zmsyslogsetup
Login zimbra account and to run command line the following.
su - zimbra
zmupdateauthkeys
Running the command line above zimbra ldap server, zimbra mailbox server, zimbra mta server in environment. if error then you can zimbra restart service.