Hi rebecca42,
Thanks for bringing this to our attention. Could you please give me the exact error message with any code that shows there?
This can sometimes happen when your Tax settings in QuickBooks do not match what you have set on the ATO's side.
If you go to the GST tab, then go to Settings > Tax Settings, you will need to configure the options there so that they match up with what the ATO is expecting.
This information includes Lodging Frequency, Accounting method and PAYG.
Would love to know more about what exactly is happening on your side to better understand this issue and resolve it.
Kristian.