Fatal error: Uncaught Error: Class "WPMailSMTP\MigrationAbstract" not found in /var/www/html1/wp-content/plugins/wp-mail-smtp/src/Queue/Migration.php:12 Stack trace: #0 {main} thrown in /var/www/html1/wp-content/plugins/wp-mail-smtp/src/Queue/Migration.php on line 12