Not able to create dataconnection for datasourceID=rest using Dcaas api link

[Anuradha-kesharkar]

I am getting below error while creating data connection for datasourceID=rest using DCAAS Api link

{

    "status": 400,

    "errors": [

        {

            "code": "DCAAS-2004",

            "title": "Unsuccessful command while creating connection",

            "meta": {

                "description": "Command 'testConnection' exection was not successful",

                "message": "Value cannot be null. (Parameter 'source')",

                "detail": null

            }

        }

    ]

}