Authorisation to access taxpayer details failed. Confirm client to agent relationship and resubmit.
Solution
You'll see this error if some of your client's details in the CU form don't match the ATO records. It could be your client's name, date of birth or TFN. These fields must match exactly to the ATO records.
For example, if there was an extra space in the client's name in the ATO records but not in your CU form, the return will be rejected.