TT will let you continue if you enter "Unknown" for the first and last name, but your return will be rejected if you try and file it electronically without a birth date for the child.
@jataxmesc is correct that TT needs a checkbox for adoption not finalized, or child not identified. The IRS does state that child does not need to be identified to take the credit if taken for the tax year after the year of te expense.
It does not seem correct to indicate that the adoption expense was a failed attempt.
