Fatal error: Uncaught Error: Class 'WPMailSMTP\Admin\PageAbstract' not found in E:\www\web\wp-content\plugins\wp-mail-smtp\src\Admin\Pages\TestTab.php:19 Stack trace: #0 {main} thrown in E:\www\web\wp-content\plugins\wp-mail-smtp\src\Admin\Pages\TestTab.php on line 19