Username and Password not accepted. SMTP could not authenticate. · Issue #1708 · PHPMailer/PHPMailer · GitHub
Still not able to send or receive mail in moodle · Issue #1709 · PHPMailer/ PHPMailer · GitHub
php mailer is not sending mail to yandexmail,gmail,hotmail systems. but mail is sending to 10 miniute email system · Issue #2177 · PHPMailer/ PHPMailer · GitHub