Creating Generic Object Definitions and Generic objects 400 Error

gistfile1.txt

//Create Object Definition
POST - localhost:3000/api/generic_object_definitions
{
  "name"        : "LoadBalancer",
  "description" : "LoadBalancer description",
  "properties"  : {
    "attributes"   : {
      "address"      : "string",
      "last_restart" : "datetime"
    },
    "associations" : {
      "vms"      : "Vm",
      "services" : "Service"
    },
    "methods"      : [
      "add_vm",
      "remove_vm"
    ]
  }
}

// Response 
{"results":[{"href":"http://localhost:3000/api/generic_object_definitions/10000000000001","id":"10000000000001","name":"LoadBalancer","description":"LoadBalancer description","properties":{"attributes":{"address":"string","last_restart":"datetime"},"associations":{"vms":"Vm","services":"Service"},"methods":["add_vm","remove_vm"]},"created_at":"2017-09-19T20:20:44Z","updated_at":"2017-09-19T20:20:44Z"}]}


//Creating a Generic Object
POST - localhost:3000/api/generic_objects
{  
   "generic_object_definition":{  
      "href":"/api/generic_object_definitions/10000000000001"
   },
   "name":"My First GO",
   "property_attributes":{  
      "address":"192.168.15.1",
      "last_restart": "2017-03-09T14:45:07Z"
   },
   "associations":{  
      "services":[  
       {"href":"api/service/10r634"}
      ]
   }
}

Response - 
{"error":{"kind":"bad_request","message":"Failed to create new generic object - undefined method `[]' for nil:NilClass","klass":"Api::BadRequestError"}}