The error, CMN.ATO.RNTLPRPTY.000120: Date property first earned rental income must be prior to the form submission end date, which occurs when the date entered for when the property first earned rental income falls outside the reporting period of the return.
To resolve it:
Check the date entered in the Rental Schedule.
Make sure the date is within the financial year covered by the return, e.g. if you're lodging a 2023–24 return, the date must be on or before 30 June 2024. A date like 01 July 2024 will trigger this error.