During the one-time web setup in the Zabbix UI, there is a bug with it properly detecting the "memory_limit" option in PHP. In PHP, it is possible to set the "memory_limit" option to "-1", which means that there is no limit. The pre-requisites page (2) of the Zabbix UI incorrectly detects this as a failed value, while in fact, no limit is sufficient for the UI to run. See the attached screenshot for details.