1. Invalid URI (Rest_no_route) Error
Detail: This error can be faced during send shipment process
Error 404: Invalid URI (code:rest_no_route)
Cause: "WooCommerce Shipment Tracking" plugin is not installed or outdated
Solution: Make sure this plugin is installed/updated on your WooCommerce account
2. Critical Error on Website (WordPress / WooCommerce)
Detail: This issue is related to the WooCommerce or WordPress side and must be investigated and resolved within your WooCommerce installation.
Error: "There has been a critical error on this website."
Solution: Common WordPress Errors Document suggests:
First, check your email to see if WordPress has sent you any details about the error. Next, enable debug mode in your wp-config.php file.
After enabling this, review the error logs located in wp-content/debug.log to find out what specifically went wrong.
Some of the most common causes you might uncover include conflicts between plugins, compatibility issues with your theme, running an incompatible PHP version, hitting the memory limit, or having corrupted WordPress files.