Opendistro Kibana 6.7.1 unable to create custom webhook alert to servicenow enpoint url

Hi Team,

Im pretty new to ELK

We have our opendistro instance running on SAP cloud. We are trying to create few monitors for cron job failure. The destination is set to custom webhook>ServiceNow endpoint url (https://xxx/servicenow/create/incident) directly.

However we are not sure what payload of format to be used in the body of the alert.
Tried the below and gave a test message however no go

Any suggestions on this situation or any example on sending kibana alerts directly to service now