diff --git a/swh/scheduler/celery_backend/listener.py b/swh/scheduler/celery_backend/listener.py
--- a/swh/scheduler/celery_backend/listener.py
+++ b/swh/scheduler/celery_backend/listener.py
@@ -3,10 +3,13 @@
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
 
-import click
 import datetime
 import logging
+import time
 import socket
+import sys
+
+import click
 
 from arrow import utcnow
 from kombu import Queue
@@ -90,7 +93,10 @@
 
         backend.commit()
         for message in messages:
-            message.ack()
+            if not message.acknowledged:
+                message.ack()
+            else:
+                logger.info('message already acknowledged: %s', message)
         actions['queue'] = []
         actions['last_send'] = utcnow()
 
@@ -99,7 +105,11 @@
         try_perform_actions()
 
     def catchall_event(event, message):
-        message.ack()
+        logger.info('event: %s, message:%s', event, message)
+        if not message.acknowledged:
+            message.ack()
+        else:
+            logger.info('message already acknowledged: %s', message)
         try_perform_actions()
 
     def task_started(event, message):
@@ -168,7 +178,22 @@
         node_id='listener-%s' % socket.gethostname(),
     )
 
-    recv.capture(limit=None, timeout=None, wakeup=True)
+    errors = 0
+    while True:
+        try:
+            recv.capture(limit=None, timeout=None, wakeup=True)
+            errors = 0
+        except KeyboardInterrupt:
+            logger.exception('Keyboard interrupt, exiting')
+            break
+        except Exception:
+            logger.exception('Unexpected exception')
+            if errors < 5:
+                time.sleep(errors)
+                errors += 1
+            else:
+                logger.error('Too many consecutive errors, exiting')
+                sys.exit(1)
 
 
 @click.command()