diff --git a/kamailio/kamailio.cfg b/kamailio/kamailio.cfg
index 575349a..eb10fd7 100644
--- a/kamailio/kamailio.cfg
+++ b/kamailio/kamailio.cfg
@@ -217,7 +217,8 @@ route[RELAY] {
     if (isbflagset(7)) {
         add_rr_param(";nat=yes");
     }
-    if (!t_relay()) {
+    # Force TCP — Kamailio hat keinen UDP-Listener
+    if (!t_relay_to_tcp()) {
         sl_send_reply("500", "Relay Error");
     }
 }