Please note that Personal Outlook/Exchange (not part of M365) is not supported at this time, in that case, it is not related to Microsoft permissions. Otherwise, if you belong to a Microsoft managed tenant and are having issue connecting your Outlook calendar, please go to this article (Admin approval for Read AI) for more information on how to request access from your Microsoft admin.
How do I know if what I am seeing is related to this?
If your Microsoft admin had not granted permissions for Read AI to connect your Outlook calendar, you would see these screens:
1. New user - onboarding: connection error
2. Banner at the top of your Read AI dashboard when you are logged in:
3. Integration page - Connection error: