diff --git a/apps/iot/src/endpoint/endpoint_http.erl b/apps/iot/src/endpoint/endpoint_http.erl
index fe9a8b6..bf9615c 100644
--- a/apps/iot/src/endpoint/endpoint_http.erl
+++ b/apps/iot/src/endpoint/endpoint_http.erl
@@ -99,7 +99,8 @@ handle_info({next_data, Id, Metric}, State = #state{buffer = Buffer, endpoint =
             {ok, RespBody} = hackney:body(ClientRef),
             hackney:close(ClientRef),
             lager:debug("[endpoint_http] url: ~p, http_code: ~p, response is: ~p", [Url, HttpCode, RespBody]),
-            {noreply, State};
+            NBuffer = endpoint_buffer:ack(Id, Buffer),
+            {noreply, State#state{buffer = NBuffer}};
         {error, Reason} ->
             lager:warning("[endpoint_http] url: ~p, get error: ~p", [Url, Reason]),
             {noreply, State}