diff --git a/kfet/views.py b/kfet/views.py
index 59985f4c..5eba3476 100644
--- a/kfet/views.py
+++ b/kfet/views.py
@@ -740,11 +740,12 @@ def kpsul_cancel_operations(request):
             'amount': opegroup['amount'],
             'on_acc__is_cof': opegroup['on_acc__cofprofile__is_cof'],
         })
+    canceled_by__trigramme = canceled_by and canceled_by.trigramme or None
     for ope in opes:
         websocket_data['opes'].append({
             'cancellation': True,
             'id': ope,
-            'canceled_by__trigramme': canceled_by.trigramme,
+            'canceled_by__trigramme': canceled_by,
             'canceled_at': canceled_at,
         })
     # Need refresh from db cause we used update on querysets