To resolve the HandiTax error where the ABN must be present in the Intermediary context (identifier), ensure you have entered all mandatory ABN fields in the sections where you have entered data into the form.
If this does not resolve, you will need to reset the credentials:
Check that you are on the latest version of HandiTax 20XX, and update where required.
Log in to HandiTax and go to the Lodgment menu.
Click Set ATO Credentials.
Even if these fields are already populated, click the ellipsis to re-select the keystore.xml file.
Re-select the credential from the drop-down menu.
Type in the password, click OK then OK again to restart HandiTax.
Return to the tax return and click Errors to confirm.