I receive the message “error sending code” when trying to create an Apple ID for a child in family sharing

I am trying to add create an Apple ID for my daughter through family sharing. When I click agree to accept the parent privacy disclosure I receive the message “error sending code” “try again”. Any ideas? Apple support unable to help after several phone calls and a trip to the Genius Bar. I am the family organizer and added my son to the account 6 months ago without difficulty. Thanks.