diff --git a/testssl.sh b/testssl.sh
index 173943c..736e677 100755
--- a/testssl.sh
+++ b/testssl.sh
@@ -6671,7 +6671,7 @@ run_server_preference() {
                fi
           fi
      fi
-     default_proto=$(get_protocol $TMPFILE)
+     [[ $ret -eq 0 ]] && default_proto=$(get_protocol $TMPFILE)
      [[ "$default_proto" == TLSv1.0 ]] && default_proto="TLSv1"
      # debugme tm_out " --> $default_proto\n"