Can you try with below body
Hello, I am trying to initiate SNMP trap test via Redfish with Model: PowerEdge R740 iDRAC Version: 4.10.10.10 and Reference: [URL]   So I POST to /redfish/v1/Dell/Managers/ /DelliDRACCardService/Actions/DelliDRACCardService.SendTestSNMPTrap, with body: {"InstanceID": "SNMPAlert.1.Destination"}, and get  "Message" :  "Invalid parameter value for InstanceID.". What would be the InstanceID? How can I figure this out?  Thank you,
Redfish body