Shared Calendar not showing in Calendar app

Hello, OllyAyles.

Thanks for getting back to us in Communities.

Are you able to see the Calendar from these steps? Share calendar accounts on Mac

"See calendar accounts you have access to

1. In the Calendar app  on your Mac, choose Calendar > Preferences, then click Accounts.
2. Select the calendar account, then click Delegation.

• • A CalDAV account appears in the “Accounts I can access” list.
  • For an Exchange account, click Add button , then enter the user name of the person who gave you access.

1. To see a delegated account’s calendars in the main Calendar window, select Show.
2. To see a delegated account’s calendars in a new window, choose Window > [account name]".

If this doesn't help, you may want to reach out to Microsoft for additional help.

Cheers!

Hello, OllyAyles.

Thank you for using Apple Support Communities.

From what I've read is that your Outlook shared calendar isn't showing on your macOS Calendar app. I'd like to help with this. Have you checked to make sure the shared calendar isn't hidden? Show or hide a calendar on Mac

I would see if the calendar shows up under a test user account as well:

How to test an issue in another user account on your Mac

Let me know what happens.

Cheers!