diff --git a/azure-mgmt-monitor/azure/mgmt/monitor/models/action_group_resource.py b/azure-mgmt-monitor/azure/mgmt/monitor/models/action_group_resource.py
index 2feb3268a1df..0ccca8947395 100644
--- a/azure-mgmt-monitor/azure/mgmt/monitor/models/action_group_resource.py
+++ b/azure-mgmt-monitor/azure/mgmt/monitor/models/action_group_resource.py
@@ -75,7 +75,7 @@ class ActionGroupResource(Resource):
         'name': {'readonly': True},
         'type': {'readonly': True},
         'location': {'required': True},
-        'group_short_name': {'required': True, 'max_length': 15},
+        'group_short_name': {'required': True, 'max_length': 12},
         'enabled': {'required': True},
     }
 
diff --git a/azure-mgmt-monitor/azure/mgmt/monitor/models/action_group_resource_py3.py b/azure-mgmt-monitor/azure/mgmt/monitor/models/action_group_resource_py3.py
index d65569ab6cb7..0a085e1e5b52 100644
--- a/azure-mgmt-monitor/azure/mgmt/monitor/models/action_group_resource_py3.py
+++ b/azure-mgmt-monitor/azure/mgmt/monitor/models/action_group_resource_py3.py
@@ -75,7 +75,7 @@ class ActionGroupResource(Resource):
         'name': {'readonly': True},
         'type': {'readonly': True},
         'location': {'required': True},
-        'group_short_name': {'required': True, 'max_length': 15},
+        'group_short_name': {'required': True, 'max_length': 12},
         'enabled': {'required': True},
     }