diff --git a/modules/module-modem-manager.c b/modules/module-modem-manager.c
index a0ab8067..490e7b5f 100644
--- a/modules/module-modem-manager.c
+++ b/modules/module-modem-manager.c
@@ -213,7 +213,7 @@ list_calls_done (GObject * obj,
   g_object_get (wpmm->dbus, "connection", &conn, NULL);
 
   g_variant_get (params, "(ao)", &calls);
-  while (g_variant_iter_loop (calls, "o", &path)) {
+  while (g_variant_iter_loop (calls, "&o", &path)) {
     g_dbus_proxy_new (conn,
                       G_DBUS_PROXY_FLAGS_NONE,
                       NULL,