Fedora 35 and 36 ship version 8.0 of PHP and version 5.0 of Zabbix, but as stated in Zabbix 5.0 Documenation: Requirements this combination is not supported. The PHP software for the Zabbix frontend needs to have version 7.2 or later, but not 8.
Cause
PHP was updated in the Fedora Linux repositories to the latest version, and there isn’t a Zabbix version that is ready for that.
After you update your system in your usual way (and possibly reboot), you should no longer be affected by this problem. If the problem persists, please start a new discussion topic and we’ll help figure out what’s still wrong.
Please ignore the message above, the update doesn’t seem to fix the issue.