diff --git a/coolamqp/clustering/cluster.py b/coolamqp/clustering/cluster.py
index 741efb41de2e7185b62354fb51009548e7f1981d..3e82cedd8ac222a30b88b0516e691e7dea4aac16 100644
--- a/coolamqp/clustering/cluster.py
+++ b/coolamqp/clustering/cluster.py
@@ -58,7 +58,7 @@ class Cluster(object):
                     on_fail()
             self.on_fail = decorated
         else:
-            self.on_fail = on_fail
+            self.on_fail = None
 
     def declare(self, obj, persistent=False):
         """