SunCertPathBuilderException: unable to find valid certification path to requested target`

Question

I know there are a lot of question regarding the same thing on SO, but I don't seem to have found the solution for my problem yet.

I am using JavaMail API to connect to a mail server. Initially I used the port 110 to connect to pop3 server and that is when I got the following exception -
javax.net.ssl.SSLException: Unrecognized SSL message, plaintext connection?

I changed the port to 995 and got the following exception -

sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target

Code for connecting to the server:

Properties props = System.getProperties();
props.setProperty("mail.store.protocol", "pop3");
props.setProperty("mail.pop3.ssl.enable", "true");

Session session = Session.getInstance(props, null);
store           = session.getStore("pop3");
store.connect(ServerName, Port, UserName, Password);

Where am I going wrong? Any advice would be helpful. Thanks in advance.

Answer 1

The first error message says it all. You're attempting SSL to a plaintext port. Try disabling SSL, or use the correct port for SSL.

The second one says that your truststore doesn't trust the server certificate. If it's self-signed, you will need to import it into your truststore.