JavaMail error + Unrecognized SSL message, plaintext connection?

Question

Using below code to read mails from a Zimbra mail server.

String SSL_FACTORY = "javax.net.ssl.SSLSocketFactory";

Properties pop3Props = new Properties();

pop3Props.setProperty("mail.pop3.socketFactory.class", SSL_FACTORY);
pop3Props.setProperty("mail.pop3.socketFactory.fallback", "false");
pop3Props.setProperty("mail.pop3.auth", "true");
pop3Props.setProperty("mail.pop3.port",  "110");
pop3Props.setProperty("mail.pop3.socketFactory.port", "110");

URLName url = new URLName("pop3", host, 110, "",username, password);

Session session = Session.getInstance(pop3Props, null);
Store store = new POP3SSLStore(session, url);
store.connect();

But keep getting this error

javax.mail.MessagingException: Connect failed;
  nested exception is:
    javax.net.ssl.SSLException: Unrecognized SSL message, plaintext connection?
    at com.sun.mail.pop3.POP3Store.protocolConnect(POP3Store.java:148)
    at javax.mail.Service.connect(Service.java:275)
    at javax.mail.Service.connect(Service.java:156)
    at javax.mail.Service.connect(Service.java:105)
    at VerifyMail.readPOP3(VerifyMail.java:177)
    at VerifyMail.main(VerifyMail.java:20)
Caused by: javax.net.ssl.SSLException: Unrecognized SSL message, plaintext connection?
    at com.sun.net.ssl.internal.ssl.InputRecord.handleUnknownRecord(Unknown Source)
    at com.sun.net.ssl.internal.ssl.InputRecord.read(Unknown Source)
    at com.sun.net.ssl.internal.ssl.SSLSocketImpl.readRecord(Unknown Source)
    at com.sun.net.ssl.internal.ssl.SSLSocketImpl.performInitialHandshake(Unknown Source)
    at com.sun.net.ssl.internal.ssl.SSLSocketImpl.readDataRecord(Unknown Source)
    at com.sun.net.ssl.internal.ssl.AppInputStream.read(Unknown Source)
    at java.io.BufferedInputStream.fill(Unknown Source)
    at java.io.BufferedInputStream.read(Unknown Source)
    at java.io.DataInputStream.readLine(Unknown Source)
    at com.sun.mail.pop3.Protocol.simpleCommand(Protocol.java:347)
    at com.sun.mail.pop3.Protocol.<init>(Protocol.java:91)
    at com.sun.mail.pop3.POP3Store.getPort(POP3Store.java:201)
    at com.sun.mail.pop3.POP3Store.protocolConnect(POP3Store.java:144)
    ... 5 more

Can anyone help on how to resolve this?

Answer 1

Read this list of common mistakes and then clean up your code.

The Gmail example should work for you as well, although obviously you'll need to change the host name.