Are you trying to connect your Commonwealth bank in your QuickBooks Self Employed account? If so, as long as the account type you have for Commonwealth bank is supported in QuickBooks you should be able to connect your bank account on file.
Here's how you can connect your bank account:
Log in to QuickBooks Self Employed using web browser.
Click on the Profile Icon, and click on Bank accounts.
Enter your bank's name or URL in the search box.
Click Continue and enter your banks log in details.
Click on Connect.
If you've connected your bank account and is getting an error, please click on Refresh all in the Bank account page.