Fatal error: Uncaught Error: Class 'WPMailSMTP\MigrationAbstract' not found in C:\xampp\htdocs\wp-content\plugins\wp-mail-smtp\src\Migration.php:17 Stack trace: #0 {main} thrown in C:\xampp\htdocs\wp-content\plugins\wp-mail-smtp\src\Migration.php on line 17