Go back and review all of your answers for the child.
Make sure that the date of birth shows the child being born in 2018, which would show them as being age 16 ins 2024. Enter the DOB in the format MM/DD/YYYY
Make sure that you indicated the child lived with you for the whole year. That there was no one else in the household supporting the child. The child did NOT provide over one-half of their own support. And that you did not check the box Not eligible for employment on the Social Security number screen.
If everything entered is correct, then delete the child as a dependent and re-enter.