diff --git a/trytond/ir/cron.py b/trytond/ir/cron.py
index 589f5f66d0..bd258f80d7 100644
--- a/trytond/ir/cron.py
+++ b/trytond/ir/cron.py
@@ -111,7 +111,7 @@ class Cron(ModelSQL, ModelView):
                     continue
                 tb_s += line
             try:
-                tb_s += error.message.decode('utf-8', 'ignore')
+                tb_s += str(error).decode('utf-8', 'ignore')
             except Exception:
                 pass