Fatal error: Uncaught Error: Interface "WPMailSMTP\Providers\MailerInterface" not found in /var/www/html/wp-content/plugins/wp-mail-smtp-pro/src/Providers/MailerAbstract.php:18 Stack trace: #0 {main} thrown in /var/www/html/wp-content/plugins/wp-mail-smtp-pro/src/Providers/MailerAbstract.php on line 18