diff --git a/lib-ee/emqx_license/src/emqx_license_checker.erl b/lib-ee/emqx_license/src/emqx_license_checker.erl
index e0d511181..bf02266d0 100644
--- a/lib-ee/emqx_license/src/emqx_license_checker.erl
+++ b/lib-ee/emqx_license/src/emqx_license_checker.erl
@@ -71,14 +71,14 @@ purge() ->
 init([LicenseFetcher, CheckInterval]) ->
     case LicenseFetcher() of
         {ok, License} ->
-            ?LICENSE_TAB = ets:new(?LICENSE_TAB, [set, protected, named_table, read_concurrency]),
+            ?LICENSE_TAB = ets:new(?LICENSE_TAB, [set, protected, named_table, {read_concurrency, true}]),
             #{} = check_license(License),
             State0 = ensure_check_license_timer(#{check_license_interval => CheckInterval,
                                    license => License}),
             State = ensure_check_expiry_timer(State0),
             {ok, State};
-        {error, _} = Error ->
-            Error
+        {error, Reason} ->
+            {stop, Reason}
     end.
 
 handle_call({update, License}, _From, State) ->
@@ -124,10 +124,11 @@ ensure_check_expiry_timer(State) ->
 
 cancel_timer(State, Key) ->
     Ref = maps:get(Key, State),
-    case is_reference(Ref) of
-        true -> erlang:cancel_timer(Ref);
-        false -> ok
-    end.
+    _ = case is_reference(Ref) of
+            true -> erlang:cancel_timer(Ref);
+            false -> ok
+        end,
+    ok.
 
 check_license(License) ->
     DaysLeft = days_left(License),
diff --git a/lib-ee/emqx_license/src/emqx_license_resources.erl b/lib-ee/emqx_license/src/emqx_license_resources.erl
index 36988c9fa..79bbc113b 100644
--- a/lib-ee/emqx_license/src/emqx_license_resources.erl
+++ b/lib-ee/emqx_license/src/emqx_license_resources.erl
@@ -76,7 +76,7 @@ code_change(_OldVsn, State, _Extra) ->
 connection_quota_early_alarm() ->
     connection_quota_early_alarm(emqx_license_checker:limits()).
 
-connection_quota_early_alarm(#{max_connections := Max}) when is_integer(Max) ->
+connection_quota_early_alarm({ok, #{max_connections := Max}}) when is_integer(Max) ->
     Count = connection_count(),
     Low = emqx_conf:get([license, connection_low_watermark], 0.75),
     High = emqx_conf:get([license, connection_high_watermark], 0.80),