Forum Discussion
Office365 / Exchange Online Calendar Sharing
You'll have to set permissions indeed, or best have an admin configure an organizaitonal relationship: https://docs.microsoft.com/en-us/exchange/sharing/organization-relationships/organization-relationships
Yes, an organizational relationship is setup already, and that seems to work fine... users in each organization can create new meetings and the scheduling assistant shows free/busy info just fine.
What we are trying to do now is allow users from Org A to add users' calendars from Org B in Outlook (desktop), so they can overlay calendars and see free/busy without having to create a meeting (and use the scheduling assistant to see availability).
Right now, users get the following error when attempting to add a calendar:
(attached)
You still need to adjust permissions even when org relationship is in place. The Default level only applies to internal users.