Office 365 Shared Calendars

Has anyone else ever come across this?

My boss and I share our Office 365 calendars with each other. I can successfully access her calendar using Outlook on the Web and Outlook on the Mac (both old and new). However, when I try to access her calendar using Apple Calendar or Fantastical, they say I don’t have permissions to view her calendar.

My guess is there’s a security setting I’m missing some place. I’ve been able to access Office 365 calendars in third-party apps in other organizations.


I’m not using any external accounts. All of the accounts involved are internal Microsoft 365 accounts on the same domain. I can access my own account in the same tenant using Apple Calendar or Fantastical just fine.

I don’t know if this would help but for me, BusyCal has been a life saver because it reliably connects to everything, including Office and Exchange accounts.

This seems to be a bit different though as it’s not the OP trying to access their own calendar, but to view someone else’s via a delegation of authority.

I suspect that OWA (Outlook Web Access) and Outlook have special access via Exchange 365 which Apple Calendar and Fantastical aren’t able to access.

I wonder if your organization could have locked it down as well. Are you able to access them through the default app in iphone?

Yes, I can! That I can do.