How to fix missing birthdays in Calendar that appears on my iPhone?

[atbw]

Using calendar 15.0 (ios 15.3.2), birthday (month/day/year) is in my contacts, have contacts synced to icloud, but does not appear in calendar, only on my iphone. I don't know how many birthdays are effected (many do appear in calendar) but my son's birthday is missing. Tried removing the birthday and then adding it back in, but no joy.

 

[ferrarr]

In the Calendar (macOS) Sidebar, do you see the Birthdays Calendar listed under Other? If not, go into Settings and enable it.

 

[Jimmysb]

In the Calendar (macOS) Sidebar, do you see the Birthdays Calendar listed under Other? If not, go into Settings and enable it.

As this is:

 

[jomacky]

I had a similar issue before, and it turned out that the birthday wasn’t syncing properly from Contacts to the Calendar, even though everything looked right. What fixed it for me was toggling the Birthdays calendar off and back on again in the Calendar app settings (under Accounts > iCloud > toggle Calendars off, then on).