How do I fix an authentication failed error for my child's iCloud information?

How do I fix an authentication failed error for my child's iCloud information?

How do I update my child's iCloud credentials due to an authentication failed error message?
If you have changed your child's iCloud credentials, please follow the steps below to configure the phone into the parent dashboard. Let's ...
Tue, 21 Mar, 2017 at 8:26 AM
How To Reset Your Child's iCloud Credentials
Are you receiving a message stating "Authentication Failed"? Authentication failed indicates that Apple is not accepting the password entered.   ...
Wed, 31 May, 2017 at 10:10 AM