diff --git a/addons/calendar/controllers/main.py b/addons/calendar/controllers/main.py
index 69bd2b9ade76a59d839a82c5e8e55aadaebfc8be..703999c440beae1a69717f86036e9f215e65e2e8 100644
--- a/addons/calendar/controllers/main.py
+++ b/addons/calendar/controllers/main.py
@@ -69,4 +69,4 @@ class CalendarController(http.Controller):
 
     @http.route('/calendar/notify_ack', type='json', auth="user")
     def notify_ack(self, type=''):
-        return request.env['res.partner']._set_calendar_last_notif_ack()
+        return request.env['res.partner'].sudo()._set_calendar_last_notif_ack()