diff --git a/addons/microsoft_calendar/models/calendar.py b/addons/microsoft_calendar/models/calendar.py
index 641c4135bc0..925eb23434a 100644
--- a/addons/microsoft_calendar/models/calendar.py
+++ b/addons/microsoft_calendar/models/calendar.py
@@ -16,6 +16,7 @@ ATTENDEE_CONVERTER_O2M = {
     'accepted': 'accepted'
 }
 ATTENDEE_CONVERTER_M2O = {
+    'none': 'needsAction',
     'notResponded': 'needsAction',
     'tentativelyAccepted': 'tentative',
     'declined': 'declined',