diff --git a/src/emqttd_gc.erl b/src/emqttd_gc.erl
index 339e895f3..9261e297e 100644
--- a/src/emqttd_gc.erl
+++ b/src/emqttd_gc.erl
@@ -25,8 +25,8 @@
 -spec(conn_max_gc_count() -> integer()).
 conn_max_gc_count() ->
     case emqttd:env(conn_force_gc_count) of
-        undefined -> undefined;
-        I when I > 0 -> I + rand:uniform(I)
+        {ok, I} when I > 0 -> I + rand:uniform(I);
+        undefined -> undefined
     end.
 
 -spec(reset_conn_gc_count(pos_integer(), tuple()) -> tuple()).