Calendar sharing with family members doesnt send invitations

Hello, we have a family of 4. All have icloud accounts and we have shared each others calendar with all other members.

The only exeption is my daughters calender.

How much we try to share it, neither of the other family members get an invitation mail or acceptation link in the calender app.

I have tried everything for so far I can think of but nothing seems to work. None of the other family members recieve anything.

Does someone has experience with this?

Thanks in Advance,

Jaco