Unable to verify WooCommerce API Settings

The most common reason that you are unable to verify the WooCommerce API settings is that your WordPress settings are still using the default Permalink options.  From your WordPress admin page, select the "Settings" option and then set your PermaLink option to one of the suggested options.  Even if you don't change anything on this page, select an entry and click the "Save Changes" button to force WordPress to use a "Pretty" permalink option.