Please take a screenshot of the plugin settings page.
Enable debug option in plugin settings and then place an order at the cart page. You will see the request and response information. Copy this info into a text file and send it via support.wooforce.com.
Our team of experts will analyze and help you resolve the problem.
If you’re using the test credentials from Auspost they need to enable the services from their end, or if you have the live credentials then the services are pre activated, make sure you have weight and dimension in all the products. and use the API mode according to the credentials provided by Auspost.