diff --git a/apps/emqx/src/emqx_listeners.erl b/apps/emqx/src/emqx_listeners.erl
index 8e6dc1ab1..8cf3852e2 100644
--- a/apps/emqx/src/emqx_listeners.erl
+++ b/apps/emqx/src/emqx_listeners.erl
@@ -38,11 +38,11 @@
 start() ->
     foreach_listeners(fun start_listener/3).
 
--spec(start_listener(atom()) -> ok).
+-spec start_listener(atom()) -> ok | {error, term()}.
 start_listener(ListenerId) ->
     apply_on_listener(ListenerId, fun start_listener/3).
 
--spec(start_listener(atom(), atom(), map()) -> ok).
+-spec start_listener(atom(), atom(), map()) -> ok | {error, term()}.
 start_listener(ZoneName, ListenerName, #{type := Type, bind := Bind} = Conf) ->
     case do_start_listener(ZoneName, ListenerName, Conf) of
         {ok, _} ->
diff --git a/apps/emqx/src/emqx_sys.erl b/apps/emqx/src/emqx_sys.erl
index 6b71b7807..2f3f782e6 100644
--- a/apps/emqx/src/emqx_sys.erl
+++ b/apps/emqx/src/emqx_sys.erl
@@ -32,8 +32,6 @@
         , uptime/0
         , datetime/0
         , sysdescr/0
-        , sys_interval/0
-        , sys_heatbeat_interval/0
         ]).
 
 -export([info/0]).
@@ -104,13 +102,9 @@ datetime() ->
         io_lib:format(
             "~4..0w-~2..0w-~2..0w ~2..0w:~2..0w:~2..0w", [Y, M, D, H, MM, S])).
 
-%% @doc Get sys interval
--spec(sys_interval() -> pos_integer()).
 sys_interval() ->
     emqx_config:get([broker, sys_msg_interval]).
 
-%% @doc Get sys heatbeat interval
--spec(sys_heatbeat_interval() -> pos_integer()).
 sys_heatbeat_interval() ->
     emqx_config:get([broker, sys_heartbeat_interval]).
 
diff --git a/apps/emqx/test/props/prop_emqx_sys.erl b/apps/emqx/test/props/prop_emqx_sys.erl
index 67718ec37..b03bbbb7f 100644
--- a/apps/emqx/test/props/prop_emqx_sys.erl
+++ b/apps/emqx/test/props/prop_emqx_sys.erl
@@ -59,6 +59,8 @@ prop_sys() ->
 
 do_setup() ->
     ok = emqx_logger:set_log_level(emergency),
+    emqx_config:put([broker, sys_msg_interval], 60000),
+    emqx_config:put([broker, sys_msg_interval], 30000),
     [mock(Mod) || Mod <- ?mock_modules],
     ok.
 
@@ -98,8 +100,6 @@ command(_State) ->
            {call, emqx_sys, uptime, []},
            {call, emqx_sys, datetime, []},
            {call, emqx_sys, sysdescr, []},
-           {call, emqx_sys, sys_interval, []},
-           {call, emqx_sys, sys_heatbeat_interval, []},
            %------------ unexpected message ----------------------%
            {call, emqx_sys, handle_call, [emqx_sys, other, state]},
            {call, emqx_sys, handle_cast, [emqx_sys, other]},