diff --git a/gnes/service/base.py b/gnes/service/base.py
index fe9bfa5a..71c9d5bc 100644
--- a/gnes/service/base.py
+++ b/gnes/service/base.py
@@ -438,8 +438,8 @@ def _run(self, ctx):
             self.logger.info('break from the event loop')
         except ComponentNotLoad:
             self.logger.error('component can not be correctly loaded, terminated')
-        except Exception as e:
-            self.logger.error("exception occured: %s" % str(e), exc_info=True)
+        except Exception as ex:
+            self.logger.error('unknown exception: %s' % str(ex), exc_info=True)
         finally:
             self.is_ready.set()
             self.is_event_loop.clear()