diff --git a/core/AmSession.cpp b/core/AmSession.cpp
index 3be1b0a6..1d3e728e 100644
--- a/core/AmSession.cpp
+++ b/core/AmSession.cpp
@@ -727,7 +727,7 @@ void AmSession::onSipRequest(const AmSipRequest& req)
     catch(const string& s) {
       ERROR("%s\n",s.c_str());
       setStopped();
-      AmSipDialog::reply_error(req, 500, "Internal Server Error");
+      AmSipDialog::reply_error(req, 500, SIP_REPLY_SERVER_INTERNAL_ERROR);
     }
     catch(const AmSession::Exception& e) {
       ERROR("%i %s\n",e.code,e.reason.c_str());