diff --git a/kamailio/registrar-role.cfg b/kamailio/registrar-role.cfg
index 546164f..9430400 100644
--- a/kamailio/registrar-role.cfg
+++ b/kamailio/registrar-role.cfg
@@ -121,7 +121,7 @@ route[ATTEMPT_AUTHORIZATION]
     }
 
     if($(proto{s.tolower}) == "udp" || $(proto{s.tolower}) == "tcp" || $(proto{s.tolower}) == "tls") {
-        $var(return_port) = "$Rp";
+        $var(return_port) = $Rp;
     } else {
         $var(return_port) = "5060";
     }