com.sun.mail.smtp.smtpaddressfailedexception: [eof]

String to = "valid.email@example.com";

Properties props = new Properties();
props.put("mail.smtp.host", "smtp.example.com");
props.put("mail.smtp.port", "587");
props.put("mail.smtp.auth", "true");
props.put("mail.smtp.starttls.enable", "true");

Session session = Session.getInstance(props, new javax.mail.Authenticator() {
    protected PasswordAuthentication getPasswordAuthentication() {
        return new PasswordAuthentication("username", "password");
    }
});

telnet smtp.example.com 587

props.put("mail.debug", "true");

import javax.mail.*;
import javax.mail.internet.*;
import java.util.Properties;

public class EmailSender {
    public static void main(String[] args) {
        String to = "valid.email@example.com";
        String from = "your.email@example.com";
        String host = "smtp.example.com";

        Properties props = new Properties();
        props.put("mail.smtp.host", host);
        props.put("mail.smtp.port", "587");
        props.put("mail.smtp.auth", "true");
        props.put("mail.smtp.starttls.enable", "true");
        props.put("mail.debug", "true");

        Session session = Session.getInstance(props, new Authenticator() {
            protected PasswordAuthentication getPasswordAuthentication() {
                return new PasswordAuthentication("username", "password");
            }
        });

        try {
            MimeMessage message = new MimeMessage(session);
            message.setFrom(new InternetAddress(from));
            message.addRecipient(Message.RecipientType.TO, new InternetAddress(to));
            message.setSubject("Test Email");
            message.setText("This is a test email.");

            Transport.send(message);
            System.out.println("Email sent successfully.");
        } catch (MessagingException mex) {
            mex.printStackTrace();
        }
    }
}