javax.mail.MessagingException: Could not connect to SMTP host?

Question

following is my code to send mail:

import java.util.Properties;
import javax.mail.Authenticator;
import javax.mail.Message;
import javax.mail.Message.RecipientType;
import javax.mail.MessagingException;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;
public class SendMail {
    public void sendMail(String m_from,String m_to,String m_subject,String m_body){
      try {
            Session m_Session;
            Message m_simpleMessage;
            InternetAddress m_fromAddress;
            InternetAddress m_toAddress;
            Properties m_properties;

            m_properties     = new Properties();
            m_properties.put("mail.smtp.host", "usdc2spam2.slingmedia.com"); 
            m_properties.put("mail.smtp.socketFactory.port", "465");
            m_properties.put("mail.smtp.socketFactory.class","javax.net.ssl.SSLSocketFactory");
            m_properties.put("mail.smtp.auth", "true");
            m_properties.put("mail.smtp.port", "9000");

            m_Session=Session.getDefaultInstance(m_properties,new Authenticator() {
                protected PasswordAuthentication getPasswordAuthentication() {
                    return new PasswordAuthentication("aaaaa","bbbbb@1"); // username and the password
                }
            });

            m_simpleMessage  =   new MimeMessage(m_Session);
            m_fromAddress    =   new InternetAddress(m_from);
            m_toAddress      =   new InternetAddress(m_to);

            m_simpleMessage.setFrom(m_fromAddress);
            m_simpleMessage.setRecipient(RecipientType.TO, m_toAddress);
            m_simpleMessage.setSubject(m_subject);

            m_simpleMessage.setContent(m_body, "text/html");

            //m_simpleMessage.setContent(m_body,"text/plain");

            Transport.send(m_simpleMessage);
        } catch (MessagingException ex) {
            ex.printStackTrace();
        }
    }
    public static void main(String[] args) {
      SendMail send_mail    =   new SendMail();
      String empName = "xxxxx";
      String title ="<b>Hi !"+empName+"</b>";
      send_mail.sendMail("123erft@slingmedia.com", "abz@gmail.com", "Please apply for leave for the following dates", title+"<br>by<br><b>HR<b>");
    }
}

but when i run the code it gives me the following exception.

javax.mail.MessagingException: Could not connect to SMTP host: usdc2spam2.slingmedia.com, port: 9000;
  nested exception is:
    java.net.ConnectException: Connection refused: connect
    at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:1934)
    at com.sun.mail.smtp.SMTPTransport.protocolConnect(SMTPTransport.java:638)
    at javax.mail.Service.connect(Service.java:317)
    at javax.mail.Service.connect(Service.java:176)
    at javax.mail.Service.connect(Service.java:125)
    at javax.mail.Transport.send0(Transport.java:194)
    at javax.mail.Transport.send(Transport.java:124)
    at samples.SendMail.sendMail(SendMail.java:46)
    at samples.SendMail.main(SendMail.java:55)
Caused by: java.net.ConnectException: Connection refused: connect
    at java.net.PlainSocketImpl.socketConnect(Native Method)
    at java.net.PlainSocketImpl.doConnect(Unknown Source)
    at java.net.PlainSocketImpl.connectToAddress(Unknown Source)
    at java.net.PlainSocketImpl.connect(Unknown Source)
    at java.net.SocksSocketImpl.connect(Unknown Source)
    at java.net.Socket.connect(Unknown Source)
    at java.net.Socket.connect(Unknown Source)
    at com.sun.mail.util.SocketFetcher.createSocket(SocketFetcher.java:288)
    at com.sun.mail.util.SocketFetcher.getSocket(SocketFetcher.java:231)
    at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:1900)

when i ping this usdc2spam2.slingmedia.com it gives me reply without any problem. I am using windows 7

Please help me to resolve this.

Answer 1

This is these two lines which was casting me the problem :

m_properties.put("mail.smtp.socketFactory.port", "465");
  m_properties.put("mail.smtp.socketFactory.class","javax.net.ssl.SSLSocketFactory");

and added this line :

m_properties.put("mail.smtp.starttls.enable", "true");

After removing and adding the above lines of code it worked fine.

Answer 2

What causes your problem is right there in the stack trace:

java.net.ConnectException: Connection refused: connect

do you need a password to connect to the SMTP server? Are you sure you are using the right settings (as in port number)? Are you behind a proxy or a firewall? Can you use those settings in a regular mail program (eg Thunderbird) and send mails?

Answer 3

尝试将端口9000添加到Windows防火墙中的入站规则中。

Answer 4

This exception usually occurs when there is no service listening on the port you are trying to connect to.

Try to connect using putty or telnet . I can bet you will get the same error.

Verify these things:

• Host name and port you're trying to connect to,
• The server is listening correctly, and
• There's no firewall blocking the connection.