Email server giving not allowing like how Gmail server allows - email

Question

I have been using Gmail to send email so now I tried to move our to a different mail server. Below is the settings.
Properties props = new Properties();
props.put("mail.smtp.host", "*******");
props.put("mail.smtp.socketFactory.port", "465");
props.put("mail.smtp.socketFactory.class","javax.net.ssl.SSLSocketFactory");
props.put("mail.smtp.auth", "true");
props.put("mail.smtp.port", "465");
Session session = Session.getDefaultInstance(props,new javax.mail.Authenticator()
{
protected PasswordAuthentication getPasswordAuthentication()
{
return new PasswordAuthentication("******","******");
}
});
Below is the error which I got.
javax.mail.MessagingException: Could not connect to SMTP host: *******, port: 465
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: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 commServer9000$MailProcessor.run(commServer9000.java:6518)
at java.lang.Thread.run(Thread.java:619)
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 com.sun.net.ssl.internal.ssl.Alerts.getSSLException(Alerts.java:174)
at com.sun.net.ssl.internal.ssl.SSLSocketImpl.fatal(SSLSocketImpl.java:1623)
at com.sun.net.ssl.internal.ssl.Handshaker.fatalSE(Handshaker.java:198)
at com.sun.net.ssl.internal.ssl.Handshaker.fatalSE(Handshaker.java:192)
at com.sun.net.ssl.internal.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1074)
at com.sun.net.ssl.internal.ssl.ClientHandshaker.processMessage(ClientHandshaker.java:128)
at com.sun.net.ssl.internal.ssl.Handshaker.processLoop(Handshaker.java:529)
at com.sun.net.ssl.internal.ssl.Handshaker.process_record(Handshaker.java:465)
at com.sun.net.ssl.internal.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:884)
at com.sun.net.ssl.internal.ssl.SSLSocketImpl.performInitialHandshake(SSLSocketImpl.java:1120)
at com.sun.net.ssl.internal.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1147)
at com.sun.net.ssl.internal.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1131)
at com.sun.mail.util.SocketFetcher.configureSSLSocket(SocketFetcher.java:507)
at com.sun.mail.util.SocketFetcher.getSocket(SocketFetcher.java:238)
at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:1900)
... 8 more

Answer 1

There are multiple causes for this type of problem. Try the following in addtion to what others are telling you.
Change all your prop keys from
mail.smtp.*
to
mail.smtps.*
I use this style:
final String ssl = isSecure ? "s" : "";
props.put("mail.smtp" + ssl + ".auth", "true");