Question about Grafana with Zabbix plugin basic setting

Hi I’m new to grafana & zabbix

I follow this guide : Configuring Grafana with Zabbix – Zabbix Blog

But now im having trouble when adding data source → save & testing

It showed error message like this

lvl=eror msg=“Zabbix API request error” logger=plugins.backend pluginId=alexanderzobnin-zabbix-datasource error=“Post “”: dial tcp connectex: No connection could be made because the target machine actively refused it.”

help please i tried in many PCs but still cannot save and test