don't refuse invites on established sessions due to session limits

src/mod/endpoints/mod_sofia/sofia.c

@@ -2061,6 +2061,7 @@ void sofia_event_callback(nua_event_t event,
 	case nua_i_notify:
 	case nua_i_info:
 
+		if (!sofia_private) {
 			if (sess_count >= sess_max || !sofia_test_pflag(profile, PFLAG_RUNNING) || !switch_core_ready_inbound()) {
 				nua_respond(nh, 503, "Maximum Calls In Progress", SIPTAG_RETRY_AFTER_STR("300"), NUTAG_WITH_THIS(nua), TAG_END());
 				goto end;
@@ -2076,6 +2077,8 @@ void sofia_event_callback(nua_event_t event,
 				nua_respond(nh, 503, "System Paused", NUTAG_WITH_THIS(nua), TAG_END());
 				goto end;
 			}
+		}
+
 		break;
 
 	default: