Since Grafana 8 migration (now 8.04), I can’t acknowledge the Zabbix alerts anymore. Everytime I click of the button (in red), the whole panel goes blank and reappear a few seconds later (probably at refresh).
This issue is/was reproducible with Zabbix server 5.4 and 5.2 and was working fine before migration (7.X).
I am guessing that the Zabbix plugin developer will need to update this in order to work with the new alerting engine. I’m not familiar with how this particular plugin works but it looks like this github issue is describing the same problem you’re having.