Unable to share a calendar with an external user

You are unable to share a secondary calendar with an external user with the Make changes to events permission.

• Google Calendar

1. In your Admin console.
2. Go to Menu > Apps > Google Workspace > Calendar. Requires having the administrator privilege.
3. Click Sharing settings.
4. To apply the setting to everyone, leave the top organizational unit selected. Otherwise, select a child organizational unit or a configuration group.
5. In the External Sharing options section, choose how your users can share their calendars with people outside your organization. 
   If you lower the external sharing level, people outside your organization may lose access to calendars they could previously see.
   • Only free/busy information (hide event details)—Check when your calendar is booked and when it has free time, but not the names or details of your events.
   • Share all information, but outsiders cannot change calendars—Find details for all events except those marked as private.
     • Find the time zone setting for the calendar. 
     • Subscribe to email alerts when events are created, changed, canceled, responded to, or coming up.
   • Share all information, and outsiders can change calendars—Find details for all events, including private ones. 
     • Add and edit events. 
     • Restore or permanently delete events from the calendar's trash. 
     • Find calendar time zone setting. 
     • Subscribe to email alerts when events are created, changed, canceled, responded to, or coming up.
   • Share all information, and allow managing of calendars—Find details for all events, including private ones. 
     • Add and edit events. 
     • Restore or permanently delete events from the calendar's trash. 
     • Find the time zone setting for the calendar. 
     • Change sharing settings. 
     • Subscribe to email alerts when events are created, changed, canceled, responded to, or coming up. 
     • Permanently delete the calendar.
6. (Optional) To set an external calendar sharing options for secondary calendars that users create, go to Google Workspace > Calendar > General. You see the same options as for primary calendars. You just can't set them for individual organizational units.

7. Click Save. If you configured an organizational unit or group, you might be able to either Inherit or Override a parent organizational unit, or Unset a group.

Changes can take up to 24 hours but typically happen more quickly.

Settings in the Admin console prohibit external users from receiving an Editor access for secondary calendars.