Serialize instance in retrieve

recircle/instance/views.py

@@ -101,7 +101,7 @@ class InstanceViewSet(AuthorizationMixin, ViewSet):
             return Response({"error": "No permission to access the Virtual Machine."},
                             status=status.HTTP_401_UNAUTHORIZED)
         instance.update_status()
-        return Response(instance)
+        return Response(InstanceSerializer(instance).data)
 
     # PUT method for updating the instance own properties BUT not the related fields
     def update(self, request, pk, format=None):