In the HandiTax report navigator, after a lodgment attempt, you may see the Error: 'VALIDATION FILE NOT FOUND'.
From HandiTax, go to the Reports menu, then click Report Navigator.
Select the Transmission/Validation Reports tab.
Highlight the report and click View Trans.
Review the reason why the return was rejected.
If you were previously lodging prior years and there have been no changes (e.g. tax agent, computer, server), the ATO may be having issues/delays with processing the validations. You can check the Help, PLS Dashboard or try to lodge the prior year again at a later time.