diff --git a/plugins/sip/calls-sip-origin.c b/plugins/sip/calls-sip-origin.c
index 2821be1..639f726 100644
--- a/plugins/sip/calls-sip-origin.c
+++ b/plugins/sip/calls-sip-origin.c
@@ -318,7 +318,7 @@ sip_authenticate (CallsSipOrigin *origin,
 
   auth = g_strdup_printf ("%s:%s:%s:%s",
                           scheme, realm, origin->user, origin->password);
-  nua_authenticate (nh, NUTAG_AUTH (auth));
+  nua_authenticate (nh, NUTAG_AUTH (auth), TAG_END ());
 }