Hi DonTimo,
Thanks for reaching out in Apple Support Communities. It sounds like you're having trouble getting your Facebook calendar to work with Calendar on your Mac and you're receiving an error. I know it's important to be able to add calendars; I'd like to help. I'd recommend using the steps below to remove the Facebook calendar, then add it back:
- In the Calendar app
on your Mac, click the calendar’s name in the calendar list. - If you don’t see the calendar list on the left, choose View > Show Calendar List.
- Choose Edit > Delete.
- Some calendars can’t be deleted.
- You can’t delete delegated calendars, but you can stop showing them in the main Calendar window. See Share calendar accounts.
- If you can’t delete a calendar for a particular calendar account, try deleting the calendar on the account provider’s website. For example, to delete a Google calendar, go to google.com.
- If a calendar account has only one calendar (not counting other people’s calendars you’re sharing), you can’t delete that last calendar.
- In the Calendar app
on your Mac, choose File > New Calendar, then choose an account for the calendar. - Name the calendar, then press Return.
If you can’t add a calendar for a particular calendar account, try adding a calendar on the account provider’s website. For example, to create a Google calendar, go to google.com."
Add or delete calendars on Mac
Let me know what you find.
Best Regards.