Dismiss the persistent "WooCommerce Shipping has successfully been installed and activated" admin notice. Use when the dismiss button fails due to blocked AJAX requests (403 errors from security plugins/firewalls).

dismiss-wcshipping-migration-notice.php

<?php
/**
 * Dismiss WooCommerce Shipping Migration Notice
 *
 * Fixes the persistent "WooCommerce Shipping has successfully been installed
 * and activated — enjoy the new WooCommerce Shipping experience." notice
 * that won't dismiss due to blocked AJAX requests (403 errors).
 *
 * Usage: Add via Code Snippets plugin (admin only), then deactivate after use.
 *
 * Cause: Security plugins (Wordfence) or server firewalls blocking admin-ajax.php.
 */

add_action( 'admin_init', function() {
    update_option( 'wcshipping_installation_completed_shown', true );
}, 1 );

/**
 * Dismiss all WooCommerce Shipping Migration Notices
 *
 * Fixes persistent migration notices that won't dismiss due to blocked AJAX requests.
 */

add_action( 'admin_init', function() {
    update_option( 'wcshipping_installation_completed_shown', true );
    update_option( 'wcshipping_migration_completed_shown', true );
}, 1 );