props.put("mail.smtp.starttls.required", "true");
props.put("mail.smtp.sasl.enable", "false");
Session session = Session.getInstance(props);
session.setDebug(debug);
final URLName unusedUrlName = null;
SMTPTransport transport = new SMTPTransport(session, unusedUrlName);
// If the password is non-null, SMTP tries to do AUTH LOGIN.
final String emptyPassword = null;
transport.connect(host, port, userEmail, emptyPassword);