Fatal error: Uncaught Error: Class 'WPMailSMTP\Providers\MailerAbstract' not found in E:\www\web\wp-content\plugins\wp-mail-smtp\src\Providers\SMTP\Mailer.php:13 Stack trace: #0 {main} thrown in E:\www\web\wp-content\plugins\wp-mail-smtp\src\Providers\SMTP\Mailer.php on line 13