The area code must begin with 0, not 61, in accordance with ATO requirements.
Ensure the correct area code has been entered in the Tax Agent Setup phone number field.
Follow the steps below to resolve the error:
Go to File.
Select Setup Manager.
Open Tax Agent Setup.
Select the relevant tax agent from the Tax Agent List.
Navigate to Telephone Numbers.
In the Phone field, verify that the area code is entered correctly and begins with 0.