Cannot delete birthday from calender on Mac
Operating system Big Sur - 11.1
I have deleted a number of contacts that had associated birthdays that appeared in the Calendar app. Whilst most of the birthdays have been removed from Calendar, some remain. They have however been removed from my iPad and iPhone. When i click on them to see the details and open the related contact card a blank contact card opens.
Any ideas how i can remove these rogue birthdays.
Thanks
MacBook Pro 13″, macOS 11.1