Error CMN.ATO.IITR.600032 states that when an amount of zero or above is present for 'Under 18' excepted net income, the 'Under 18 action code' must be provided.
Log in to HandiTax and locate your client.
Hightlight your client then click TaxForms, Edit.
In the Client's Tax Form Details window 'Over 18', drop down the arrow and select Excepted or Minor.
Excepted - the taxpayer is a minor, and is an excepted person
Minor - the taxpayer is a minor and is not an excepted person.
Click Save.
Open the tax form, and the code will be prefilled at item A1.