Unable to display host name or IP after sending alerts in slack

I have configured open distro with ELK stack and did run some alerting rules to send alerts to slack channel but when it sends alerts, under triggers i tried to give Host: {{_source.host.name}} to display even the host IP or name inslack so we know on which host the alert has been triggered when we look into slack but message preview under tirggers doesnt show up IP and i have to manually give the IP to the message for displaying on slack is there a work around and in kibana discover i checked host.name : “ip address” does exist

Dear Krishnaprateek6
Can you please show your trigger message block?