The error is based on the design of the rules by the ATO.

Error states that A4 deductions cannot be more that Total of D1-D15 fields. This means amount at A4 deductions should be also shown in one of D1-D15 fields.

Working Holiday Maker income should be both entered in salary and wages and in A4.

Validation message says that "Deductions and business losses" cannot be more than sum of total deductions and losses.

 This means, it should share the amount in these values too. 

ATO instruction states that WHM income and deductions in A4 should also be shown on tax return in income or deductions. This means that figures in A4 Working holiday maker net income should also be included in 1-24 fields and D1-D15 fields accordingly.

Also, make sure to  please update this part- 

If the client is a non-resident for full year, specify the date via "Adjustment" tab. The system will automatically treat is as a whole year non-resident (ie, client returned to Australia on 28th March 2020 and resumed his residency from that date onwards indefinitely. ) 

Adding "30 June" at the end date box is only applies for the first year of taxpayer with incomplete year.   In the next succeeding year since the taxpayer is already a resident, then adding dates to those boxes are not necessary.