As an intermediary, this issue occurs if the SMSF has not provided authority to your organisation to manage their account with the ATO. As such, the ATO is failing any request that is coming through for validation. Please ensure that authority has been provided and if so, please confirm that the authority has been provided to the ABN and TAN/RAN (if applicable) that has been given to wrkr.
If there is a discrepancy in the details authorised with the ATO and provided with wrkr, please confirm the details that are registered with the ATO. We will need to change the details recorded with wrkr and obtain a new service agreement under the new details.