diff --git a/kamailio/registrar-role.cfg b/kamailio/registrar-role.cfg
index e0a2d06..d8332ed 100644
--- a/kamailio/registrar-role.cfg
+++ b/kamailio/registrar-role.cfg
@@ -215,7 +215,7 @@ onreply_route[KZ_AUTHORIZATION_OK]
         #!ifdef ANTIFLOOD_ROLE
         route(ANITFLOOD_FAILED_AUTH);
         #!endif
-        auth_challenge("$fd", "21");
+        auth_challenge("$fd", "5");
         xlog("L_INFO", "$ci|end|challenging $Au $si:$sp via $(kzR{kz.json,App-Name})-$(kzR{kz.json,App-Version}) response\n");
         exit;
     } else {
@@ -235,7 +235,7 @@ route[CHECK_AUTHORIZATION]
         #!endif
 
         xlog("L_WARNING", "$ci|end|issuing auth challenge to failed registration attempt for $Au from IP $si:$sp\n");
-        auth_challenge("$fd", "21");
+        auth_challenge("$fd", "5");
         exit;
     }