.SMTPSendFailedException: 553 Sorry, over your daily relay limit.

I am using javamail to send mails through SMTP .

I am using authentication at server

I can send the email through the same email id by Outlook express but
when I try to send email by javamail it gives me
exception .SMTPSendFailedException: 553 Sorry, over your daily relay
limit.

Below is the java code that I am using
import javax.mail.*;
import javax.mail.internet.*;
import java.util.*;
import java.io.*;
public class SendMailUsingAuthentication
{

  private static final String SMTP_HOST_NAME =
"myserver.smtphost.com";
  private static final String SMTP_AUTH_USER = "myusername";
  private static final String SMTP_AUTH_PWD = "mypwd";

  private static final String emailMsgTxt = "Online Order
Confirmation Message. Also include the Tracking Number.";
  private static final String emailSubjectTxt = "Order Confirmation
Subject";
  private static final String emailFromAddress =
"divyendu@toy4education.com";

  // Add List of Email address to who email needs to be sent to
  private static final String[] emailList = {"abc@yahoo.com",
"xyz@yahoo.com"};

  public static void main(String args[]) throws Exception
  {
    SendMailUsingAuthentication smtpMailSender = new
SendMailUsingAuthentication();
    smtpMailSender.postMail( emailList, emailSubjectTxt, emailMsgTxt,
emailFromAddress);
    System.out.println("Sucessfully Sent mail to All Users");
  }

  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", SMTP_HOST_NAME);
     props.put("mail.smtp.auth", "true");

    Authenticator auth = new SMTPAuthenticator();
    Session session = Session.getDefaultInstance(props, auth);

    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 < recipients.length; i++)
    {
        addressTo[i] = new InternetAddress(recipients[i]);
    }
    msg.setRecipients(Message.RecipientType.TO, addressTo);

    // Setting the Subject and Content Type
    msg.setSubject(subject);
    msg.setContent(message, "text/plain");
    Transport.send(msg);
 }

/**
* SimpleAuthenticator is used to do simple authentication
* when the SMTP server requires it.
*/
private class SMTPAuthenticator extends javax.mail.Authenticator
{

    public PasswordAuthentication getPasswordAuthentication()
    {
        String username = SMTP_AUTH_USER;
        String password = SMTP_AUTH_PWD;
        return new PasswordAuthentication(username, password);
    }
}

}