diff --git a/apps/kolab_guam/src/kolab_guam_listener.erl b/apps/kolab_guam/src/kolab_guam_listener.erl
--- a/apps/kolab_guam/src/kolab_guam_listener.erl
+++ b/apps/kolab_guam/src/kolab_guam_listener.erl
@@ -73,8 +73,9 @@
                 listen_options(none, Addr, ImplicitTLS, TLSConfig)
     end.
 
-default_listen_options(true, TLSConfig) -> [ { reuseaddr, true }, {active, once } | TLSConfig ];
-default_listen_options(_ImplicitTLS, _Config) ->  [ { active, once }, { reuseaddr, true } ].
+default_listen_options(true, TLSConfig) -> default_listen_options() ++ TLSConfig;
+default_listen_options(_ImplicitTLS, _Config) -> default_listen_options().
+default_listen_options() -> [ { reuseaddr, true }, {active, once } ].
 
 create_initial_listeners(PID) when is_pid(PID) ->
     lager:debug("Creating session pool for listener ~p", [PID]),