OrderSerializer#changes_allowed_until returns 'Not allowed' unless changes are allowed

app/serializers/api/order_serializer.rb

@@ -19,6 +19,7 @@ module Api
     end
 
     def changes_allowed_until
+      return I18n.t(:not_allowed) unless object.changes_allowed?
       I18n.l(object.order_cycle.andand.orders_close_at, format: :long)
     end
 

config/locales/en.yml

@@ -645,6 +645,7 @@ en:
   terms_of_service: "Terms of service"
   on_demand: On demand
   none: None
+  not_allowed: Not allowed
 
   label_shops: "Shops"
   label_map: "Map"