This article describes a Legacy API error. Check API Type in WooCommerce → Settings → Shipping → Canada Post Live Rates before following these instructions.
If you use REST API, check the application’s API Key, API Secret, and Rating access instead. Follow REST API troubleshooting. A REST 403 response does not by itself identify the Legacy AA004 error.
AAA Authentication Failure
Connection with Canada Post API could not be established. Please verify if the data you have entered is correct and make sure that there are no typos, spelling mistakes or unnecessary signs e.g. spaces, especially if the credentials were copied and pasted.
If you are 100% sure the credentials you’ve typed in are entered correctly, and you are still getting the authentication/validation error, please contact the Canada Post support →