Fatal error: Uncaught Error: Undefined constant "PHPMailer\PHPMailer\FILTER_FLAG_HOST_REQUIRED" in /home/hrcareersolutions/vendor_hrcareersolutions_com/plugins/phpmailer/PHPMailer.php:3599 Stack trace: #0 /home/hrcareersolutions/vendor_hrcareersolutions_com/plugins/phpmailer/PHPMailer.php(3565): PHPMailer\PHPMailer\PHPMailer::isValidHost() #1 /home/hrcareersolutions/vendor_hrcareersolutions_com/plugins/phpmailer/PHPMailer.php(2304): PHPMailer\PHPMailer\PHPMailer->serverHostname() #2 /home/hrcareersolutions/vendor_hrcareersolutions_com/plugins/phpmailer/PHPMailer.php(1421): PHPMailer\PHPMailer\PHPMailer->createHeader() #3 /home/hrcareersolutions/vendor_hrcareersolutions_com/plugins/phpmailer/PHPMailer.php(1316): PHPMailer\PHPMailer\PHPMailer->preSend() #4 /home/hrcareersolutions/vendor_hrcareersolutions_com/plugins/mailclass.php(38): PHPMailer\PHPMailer\PHPMailer->send() #5 /home/hrcareersolutions/vendor_hrcareersolutions_com/register.php(6): sendmail() #6 {main} thrown in /home/hrcareersolutions/vendor_hrcareersolutions_com/plugins/phpmailer/PHPMailer.php on line 3599