Fix WooCommerce Shipping API Error on WordPress Website

I’m looking for an experienced WordPress/WooCommerce developer to troubleshoot and fix a shipping issue on my website. A customer in Australia is trying to purchase an item from my online shop, but he is unable to proceed past the shipping section. The checkout displays the following error: “Shipment: ERROR: Invalid API key” It also says “Enter a different address.” I believe the issue may be related to the shipping integration/API configuration or the international shipping settings, but I need someone to identify the exact cause and fix it. I would like you to: Identify what is causing the “Invalid API key” shipping error. Check the current shipping plugin/integration and API configuration. Verify that international shipping, particularly shipping to Australia, is properly configured. Test the checkout process to ensure customers can successfully enter an international address and receive a shipping rate. Make any necessary corrections so the shipping system works properly. The website is built on WordPress and uses WooCommerce. I can provide access to the WordPress/WooCommerce dashboard and any other information needed to troubleshoot the issue. Please only apply if you have experience troubleshooting WooCommerce shipping/API issues. I would prefer someone who can diagnose the underlying problem rather than simply work around the error. I have also attached a screenshot of the error the customer is receiving.