diff --git a/rel/files/app.config b/rel/files/app.config
index 15fc6dc02..6d2c17c06 100644
--- a/rel/files/app.config
+++ b/rel/files/app.config
@@ -51,10 +51,12 @@
     ]},
     {listen, [
         {mqtt, 1883, [
+            {backlog,   512},
             {max_clients, 1024},
             {acceptor_pool, 4}
         ]},
         {mqtts, 8883, [
+            {backlog,   128},
             {max_clients, 1024},
             {acceptor_pool, 4},
             %{cacertfile, "etc/ssl/cacert.pem"},