diff --git a/services/operation_services.py b/services/operation_services.py
index f331ed4db75cb23afd1b11ba53f12d080e48029c..1485c1e2872a11a901cecaf6c0a2efe991e2a0d0 100644
--- a/services/operation_services.py
+++ b/services/operation_services.py
@@ -631,7 +631,7 @@ class OperationsService(Component):
             "role": role,
             "id": operation.id,
             "name": operation.name,
-            "email": operation.sudo().mail_contact,
+            "email": operation.sudo().mail_contact or "",
         }
 
         return datas
@@ -737,7 +737,7 @@ class OperationsService(Component):
             },
             "id": {"type": "integer"},
             "name": {"type": "string"},
-            "email": {"type": "string"},
+            "email": {"type": "string", "nullable": True},
         }
 
     def _validator_get_doc(self):