diff --git a/apps/iot/src/http/http_server.erl b/apps/iot/src/http/http_server.erl
index 0f1c535..f23fc61 100644
--- a/apps/iot/src/http/http_server.erl
+++ b/apps/iot/src/http/http_server.erl
@@ -89,7 +89,12 @@ parse_body(Req0) ->
     case ContentType of
         <<"application/json", _/binary>> ->
             {ok, Body, Req1} = read_body(Req0),
-            {ok, catch jiffy:decode(Body, [return_maps]), Req1};
+            case Body =/= <<"">> of
+                 true ->
+                    {ok, catch jiffy:decode(Body, [return_maps]), Req1};
+                false ->
+                    {ok, #{}, Req1}
+            end;
         <<"application/x-www-form-urlencoded">> ->
             {ok, PostParams0, Req1} = cowboy_req:read_urlencoded_body(Req0),
             PostParams = maps:from_list(PostParams0),
diff --git a/apps/iot/src/mnesia/service_config_model.erl b/apps/iot/src/mnesia/service_config_model.erl
index ba46c0b..f37fa2b 100644
--- a/apps/iot/src/mnesia/service_config_model.erl
+++ b/apps/iot/src/mnesia/service_config_model.erl
@@ -89,7 +89,20 @@ get_config(ServiceId) when is_binary(ServiceId) ->
 
 -spec delete(ServiceId :: binary()) -> ok | {error, Reason :: any()}.
 delete(ServiceId) when is_binary(ServiceId) ->
-    case mnesia:transaction(fun() -> mnesia:delete(?TAB, ServiceId, write) end) of
+    Fun = fun() ->
+        case mnesia:read(?TAB, ServiceId, write) of
+            [] ->
+                ok;
+            [ServiceConfig0 = #service_config{config_json = OldConfigJson}] ->
+                NServiceConfig = ServiceConfig0#service_config{
+                    config_json = <<"">>,
+                    last_config_json = OldConfigJson,
+                    update_ts = iot_util:current_time()
+                },
+                mnesia:write(?TAB, NServiceConfig, write)
+        end
+          end,
+    case mnesia:transaction(Fun) of
         {'atomic', ok} ->
             ok;
         {'aborted', Reason} ->
diff --git a/config/vm.args b/config/vm.args
index d7b21cd..ebb0cf6 100644
--- a/config/vm.args
+++ b/config/vm.args
@@ -1,4 +1,4 @@
--sname iot
+-name iot
 
 -setcookie iot_cookie