Javamail - Could not connect to SMTP host

Question

I'm trying to send email from my java and I couldn't connect to my host. Here my codes:

public class sendEmail implements Runnable{
     @Override
     public void run(){
        try{
            final String username = "user", password = "pass", from = "[email protected]", to = "[email protected]";

            Properties props = new Properties();
            props.setProperty("mail.smtp.user", username);
            props.setProperty("mail.smtp.host", "mail.host.com");
            props.setProperty("mail.smtp.ssl.enable", "true"); 
            props.setProperty("mail.smtp.port", "465");
            props.setProperty("mail.smtp.starttls.enable", "true");
            props.setProperty("mail.smtp.debug", "true");
            props.setProperty("mail.smtp.auth", "true");
            props.setProperty("mail.smtp.socketFactory.port", "465");
            props.setProperty("mail.smtp.socketFactory.class", "javax.net.ssl.SSLSocketFactory");
            props.setProperty("mail.smtp.socketFactory.fallback", "false");
            Authenticator auth = new SMTPAuthenticator();
            Session session = Session.getInstance(props, auth);
            session.setDebug(true);

            Message msg = new MimeMessage(session);
            try{
                msg.setSubject("Test SMTP");
                msg.setFrom(new InternetAddress(from));
                msg.setRecipients(Message.RecipientType.TO, InternetAddress.parse(to));
                Transport transport = session.getTransport("smtp");
                transport.connect("mail.itbuntuksemua.com", username, password);
                transport.sendMessage(msg, msg.getAllRecipients());
                transport.close();
                System.out.println("Done");
            }catch(MessagingException | NumberFormatException | HeadlessException ex){
                ex.printStackTrace();
            }
        }catch(UnknownHostException | NumberFormatException ex){
            ex.printStackTrace();
        }
     }
 }

and here my SMTPAuthenticator() codes:

private class SMTPAuthenticator extends javax.mail.Authenticator {
    @Override
    public PasswordAuthentication getPasswordAuthentication() {
        String username = "user"; 
        String password = "pass";
        return new PasswordAuthentication(username, password);
    } 
}

and here again, my report bugs :

DEBUG: setDebug: JavaMail version 1.4.7 DEBUG: getProvider() returning javax.mail.Provider[TRANSPORT,smtp,com.sun.mail.smtp.SMTPTransport,Oracle] DEBUG SMTP: useEhlo true, useAuth true DEBUG SMTP: trying to connect to host "mail.host.com", port 465, isSSL true javax.mail.MessagingException: Could not connect to SMTP host: mail.host.com, port: 465; nested exception is: javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:1961) at com.sun.mail.smtp.SMTPTransport.protocolConnect(SMTPTransport.java:654) at javax.mail.Service.connect(Service.java:295) at javax.mail.Service.connect(Service.java:176) at scam.ccChecker$sendEmail.run(ccChecker.java:186) at java.lang.Thread.run(Thread.java:745) Caused by: javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target at sun.security.ssl.Alerts.getSSLException(Alerts.java:192) at sun.security.ssl.SSLSocketImpl.fatal(SSLSocketImpl.java:1937) at sun.security.ssl.Handshaker.fatalSE(Handshaker.java:302) at sun.security.ssl.Handshaker.fatalSE(Handshaker.java:296) at sun.security.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1478) at sun.security.ssl.ClientHandshaker.processMessage(ClientHandshaker.java:212) at sun.security.ssl.Handshaker.processLoop(Handshaker.java:957) at sun.security.ssl.Handshaker.process_record(Handshaker.java:892) at sun.security.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:1050) at sun.security.ssl.SSLSocketImpl.performInitialHandshake(SSLSocketImpl.java:1363) at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1391) at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1375) at com.sun.mail.util.SocketFetcher.configureSSLSocket(SocketFetcher.java:549) at com.sun.mail.util.SocketFetcher.createSocket(SocketFetcher.java:354) at com.sun.mail.util.SocketFetcher.getSocket(SocketFetcher.java:211) at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:1927) ... 5 more Caused by: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target at sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:387) at sun.security.validator.PKIXValidator.engineValidate(PKIXValidator.java:292) at sun.security.validator.Validator.validate(Validator.java:260) at sun.security.ssl.X509TrustManagerImpl.validate(X509TrustManagerImpl.java:324) at sun.security.ssl.X509TrustManagerImpl.checkTrusted(X509TrustManagerImpl.java:229) at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(X509TrustManagerImpl.java:124) at sun.security.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1460) ... 16 more Caused by: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target at sun.security.provider.certpath.SunCertPathBuilder.build(SunCertPathBuilder.java:145) at sun.security.provider.certpath.SunCertPathBuilder.engineBuild(SunCertPathBuilder.java:131) at java.security.cert.CertPathBuilder.build(CertPathBuilder.java:280) at sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:382) ... 22 more

can someone help me? :(

Answer 1

You might want to try downloading the certificate, install it using keytool, then set them as system variables. Here's how:

1. Go to URL in your firefox browser, click on HTTPS certificate chain (next to URL address). Click "more info" > "security" > "show certificate" > "details" > "export..". Pickup the name and choose file type example.der. Now you have file with keystore and you have to add it to your JVM
2. Locate the file $JAVA_HOME/jre/lib/security/cacerts

3. Import the example.der file into the cacerts file using the following:

   sudo keytool -import -alias example -keystore  $JAVA_HOME/jre/lib/security/cacerts -file example.der
   

4. The default keystore password is 'changeit'

5. You can view the change that you made with this command that shows the Certificate fingerprint.

   keytool -list -keystore cacerts
   

6. If this doesn't solve the problem, try adding these java options as arguments:

   -Djavax.net.ssl.trustStore="$JAVA_HOME/jre/lib/security/cacerts"
   -Djavax.net.ssl.trustStorePassword="changeit"
   

7. Or you can put them in as system variables in your java code:

   System.setProperty("javax.net.ssl.trustStore","/usr/lib/jvm/java-1.7.0-openjdk-amd64/jre/lib/security/cacerts");
   System.setProperty("javax.net.ssl.trustStorePassword","changeit");
   

More instructions can be found here: https://stackoverflow.com/a/36427118/1696153

Answer 2

Maybe you can try to set certificate, to access the SMTP port. Something like that:

System.setProperty("javax.net.ssl.trustStore","key");
System.setProperty("javax.net.ssl.trustStorePassword","password");