Hi @sapnasarkar ,

you defined only 2 properties but you are trying to access 19 of them via input.yourParameter

so to make it working, you only define first 2 parameters and rest must be empty string if you don't have that data at the time you are making the call. If you have all the data when you are making this call, I suggest that you convert your data into object and instead passing only owner and volume_type, you will pass whole objects here and adjust your code to work with that object so that you can pass the parameters dynamically.

var r = new sn_ws.RESTMessageV2('hcm launchstack-post', 'POST');
r.setStringParameterNoEscape('Owner', input.Owner);
r.setStringParameterNoEscape('volume_type', input.volume_type);
r.setStringParameterNoEscape('Support', "");
r.setStringParameterNoEscape('Application', "");
r.setStringParameterNoEscape('Description', "");
r.setStringParameterNoEscape('subnet_id', "");
r.setStringParameterNoEscape('Stack_Name', "");
r.setStringParameterNoEscape('name', "");
r.setStringParameterNoEscape('region', "");
r.setStringParameterNoEscape('Environment', "");
r.setStringParameterNoEscape('BU', "");
r.setStringParameterNoEscape('instance_type', "");
r.setStringParameterNoEscape('SubscriptionID', "");
r.setStringParameterNoEscape('AvailabilityTime', "");
r.setStringParameterNoEscape('key_name', "");
r.setStringParameterNoEscape('SharedCost', "");
r.setStringParameterNoEscape('vpc_id', "");
r.setStringParameterNoEscape('CostCenter', "");
r.setStringParameterNoEscape('Cloud', "");
r.setStringParameterNoEscape('ami', "");

If my answer helped you in any way, please then mark it as helpful or correct. This will help others finding a solution.