Cannot turn on screentime sharing for child
I have my children added to Family Sharing but cannot turn on the Screen Time sharing. I go to turn it on and it asks for my children's icloud account. Once I enter it, it says they have already been added. I have turned on Screen Time on my child's phone.
How do I turn on Screen Time for a child that is already added to Family Sharing.
iPhone 7 Plus, iOS 12