For Zabbix server installation you may need to change one or more php directives depending on the version of Zabbix server being installed.
Here’s some that I had to change,
[root@zabbix ~]# egrep -i '(max_execution_time|date.timezone|mbstring.func_overload|memory_limit)' /etc/php.ini max_execution_time = 300 ; Maximum execution time of each script, in seconds memory_limit = 128M ; Maximum amount of memory a script may consume date.timezone = "America/New_York" mbstring.func_overload = 2
Make sure that you remove the prefix “;” if you are changing an ignored directive and do not forget to restart httpd. 
