title: JavaMail: Could not connect to SMTP server
body: <p>The following code causes an error.  Please help me understand what's wrong.</p>
  
  <pre><code>import javax.mail.*;
  import javax.mail.internet.*;
  import java.util.*;
  public class SendMail
  {
    public static void main(String [] args)throws MessagingException
    {
      SendMail sm=new SendMail();
       sm.postMail(new String[]{"abc@yahoo.co.in"},"hi","hello","xyz@gmail.com");
     }
  
  public void postMail( String recipients[ ], String subject, String message , String from) throws MessagingException
  {
      boolean debug = false;
  
       //Set the host smtp address
       Properties props = new Properties();
       props.put("mail.smtp.host", "webmail.emailmyname.com");
  
      // create some properties and get the default Session
      Session session = Session.getDefaultInstance(props, null);
      session.setDebug(debug);
  
      // create a message
      Message msg = new MimeMessage(session);
  
      // set the from and to address
      InternetAddress addressFrom = new InternetAddress(from);
      msg.setFrom(addressFrom);
  
      InternetAddress[] addressTo = new InternetAddress[recipients.length]; 
      for (int i = 0; i &lt; recipients.length; i++)
      {
          addressTo[i] = new InternetAddress(recipients[i]);
      }
      msg.setRecipients(Message.RecipientType.TO, addressTo);
  
  
      // Optional : You can also set your custom headers in the Email if you Want
      msg.addHeader("MyHeaderName", "myHeaderValue");
  
      // Setting the Subject and Content Type
      msg.setSubject(subject);
      msg.setContent(message, "text/plain");
      Transport.send(msg);
  }
  }
  
  Exception:
  &lt;pre&gt;
  com.sun.mail.smtp.SMTPSendFailedException: 450 smtpout04.dca.untd.com Authentication required
  
      at com.sun.mail.smtp.SMTPTransport.issueSendCommand(SMTPTransport.java:1829)
      at com.sun.mail.smtp.SMTPTransport.mailFrom(SMTPTransport.java:1368)
      at com.sun.mail.smtp.SMTPTransport.sendMessage(SMTPTransport.java:886)
      at javax.mail.Transport.send0(Transport.java:191)
      at javax.mail.Transport.send(Transport.java:120)
      at SendMail.postMail(SendMail.java:52)
      at SendMail.main(SendMail.java:10)
  </code></pre>
  
  <p></p>