While sending an email thru a java program, it is giving the following error:

javax.mail.MessagingException: 553 Authentication required for this domain

This program was working till previously but later our company has put some kind of authentication on the outgoing mail server. From then onwards i am facing this problem. can anyone help me??? I'm attaching the code.

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import javax.mail.*;
import javax.mail.internet.*;
import javax.activation.*;
import java.io.*;

public class SendMail{

// This constructor composes the message and sends email.

public static void main(String[] args){
SendMail sm = new SendMail("username@yahoo.com","hello",args);
System.out.println("Mail sent");
}

public SendMail(String to, String sub, String[] msgs){
Properties props = new Properties();
props.put("mail.smtp.host","server.cmcltd.com");
Session session = Session.getDefaultInstance(props,null);
try{
MimeMessage msg = new MimeMessage(session);
msg.setFrom(new InternetAddress("username@cmcltd.com"));
InternetAddress address = new InternetAddress(to);
msg.setRecipient(Message.RecipientType.TO,address);
msg.setSubject(sub);
msg.setSentDate(new Date());

MimeBodyPart[] mbp = new MimeBodyPart[msgs.length + 3];
for(int j=0; j
mbp[j] = new MimeBodyPart();

int i;
for(i=0; i
mbp[i].setText(msgs[i]);
}

mbp[i++].setText("===================================");
mbp[i++].setText("Thanks & Regards");
mbp[i++].setText("KM Administrator");

Multipart mp = new MimeMultipart();

for(i=0; i
mp.addBodyPart(mbp[i]);
msg.setContent(mp);
Transport.send(msg);
}catch(Exception ex){
System.out.println(ex);
}
}
}