The error IITR.210035 appears when the Australian Government rebate received amount is greater than or equal to the premiums eligible for the rebate. This is based on ATO specifications and cannot be changed.
Log in to HandiTax and Select the tax return.
Edit to the main form I and go to the Private Health Insurance policy detail section.
Refer to your private health insurance statement.
Enter only the amounts shown on the statement into:
Your premiums eligible for Australian Government rebate.
Your Australian Government rebate received.
If the amounts have been entered correctly and the error still appears, contact the ATO for further guidance. They may require a paper lodgment.