Javamail java.security.cert.CertPathValidatorException when receiving mail from pop3

Question

So I'm trying to build an Android app that cheks email from my university's server. It works fine with Gmail. I added the certificate (.cer file) to keystore, I tried with the following properties:

        Properties properties = new Properties();
        properties.put("mail.store.protocol", "pop3");
        properties.put("mail.pop3.host", pop3Host);
        properties.put("mail.pop3.port", "995");
        properties.put("mail.pop3.starttls.enable", "true");
        properties.put("mail.pop3.ssl.checkserveridentity", "false");
        properties.put("mail.pop3.ssl.trust", "*");
        Session emailSession = Session.getDefaultInstance(properties);  

...and nothing :(

DEBUG:

stefan.studmail I/System.out﹕ DEBUG: setDebug: JavaMail version 1.5.3
stefan.studmail I/System.out﹕ DEBUG: getProvider() returning javax.mail.Provider[STORE,pop3s,com.sun.mail.pop3.POP3SSLStore,Oracle]
stefan.studmail W/art﹕ Before Android 4.1, method javax.mail.Session com.sun.mail.pop3.POP3Store.getSession() would have incorrectly overridden the package-private method in javax.mail.Service
stefan.studmail I/System.out﹕ DEBUG POP3: mail.pop3s.rsetbeforequit: false
stefan.studmail I/System.out﹕ DEBUG POP3: mail.pop3s.disabletop: false
stefan.studmail I/System.out﹕ DEBUG POP3: mail.pop3s.forgettopheaders: false
stefan.studmail I/System.out﹕ DEBUG POP3: mail.pop3s.cachewriteto: false
stefan.studmail I/System.out﹕ DEBUG POP3: mail.pop3s.filecache.enable: false
stefan.studmail I/System.out﹕ DEBUG POP3: mail.pop3s.keepmessagecontent: false
stefan.studmail I/System.out﹕ DEBUG POP3: mail.pop3s.starttls.enable: false
stefan.studmail I/System.out﹕ DEBUG POP3: mail.pop3s.starttls.required: false
stefan.studmail I/System.out﹕ DEBUG POP3: mail.pop3s.apop.enable: false
stefan.studmail I/System.out﹕ DEBUG POP3: mail.pop3s.disablecapa: false
stefan.studmail I/System.out﹕ DEBUG POP3: connecting to host "stud.usv.ro", port 995, isSSL true
stefan.studmail I/Timeline﹕ Timeline: Activity_idle id: android.os.BinderProxy@37e721f4 time:14882263
stefan.studmail E/StudMail:﹕ Connect failed
stefan.studmail W/System.err﹕ javax.mail.MessagingException: Connect failed;
stefan.studmail W/System.err﹕ nested exception is:
stefan.studmail W/System.err﹕ javax.net.ssl.SSLHandshakeException: java.security.cert.CertPathValidatorException: Trust anchor for certification path not found.
stefan.studmail W/System.err﹕ at com.sun.mail.pop3.POP3Store.protocolConnect(POP3Store.java:213)
stefan.studmail W/System.err﹕ at javax.mail.Service.connect(Service.java:364)
stefan.studmail W/System.err﹕ at javax.mail.Service.connect(Service.java:245)
stefan.studmail W/System.err﹕ at senegeac.stefan.studmail.FetchPop.fetch(FetchPop.java:75)
stefan.studmail W/System.err﹕ at senegeac.stefan.studmail.FetchPop.doInBackground(FetchPop.java:145)
stefan.studmail W/System.err﹕ at senegeac.stefan.studmail.FetchPop.doInBackground(FetchPop.java:39)
stefan.studmail W/System.err﹕ at android.os.AsyncTask$2.call(AsyncTask.java:297)
stefan.studmail W/System.err﹕ at java.util.concurrent.FutureTask.run(FutureTask.java:237)
stefan.studmail W/System.err﹕ at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
stefan.studmail W/System.err﹕ at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
stefan.studmail W/System.err﹕ at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
stefan.studmail W/System.err﹕ at java.lang.Thread.run(Thread.java:818)
stefan.studmail W/System.err﹕ Caused by: javax.net.ssl.SSLHandshakeException: java.security.cert.CertPathValidatorException: Trust anchor for certification path not found.
stefan.studmail W/System.err﹕ at com.android.org.conscrypt.OpenSSLSocketImpl.startHandshake(OpenSSLSocketImpl.java:306)
stefan.studmail W/System.err﹕ at com.sun.mail.util.SocketFetcher.configureSSLSocket(SocketFetcher.java:574)
stefan.studmail W/System.err﹕ at com.sun.mail.util.SocketFetcher.createSocket(SocketFetcher.java:369)
stefan.studmail W/System.err﹕ at com.sun.mail.util.SocketFetcher.getSocket(SocketFetcher.java:236)
stefan.studmail W/System.err﹕ at com.sun.mail.pop3.Protocol.<init>(Protocol.java:112)
stefan.studmail W/System.err﹕ at com.sun.mail.pop3.POP3Store.getPort(POP3Store.java:264)
stefan.studmail W/System.err﹕ at com.sun.mail.pop3.POP3Store.protocolConnect(POP3Store.java:207)
stefan.studmail W/System.err﹕ ... 11 more
stefan.studmail W/System.err﹕ Caused by: java.security.cert.CertificateException: java.security.cert.CertPathValidatorException: Trust anchor for certification path not found.
stefan.studmail W/System.err﹕ at com.android.org.conscrypt.TrustManagerImpl.checkTrusted(TrustManagerImpl.java:323)
stefan.studmail W/System.err﹕ at com.android.org.conscrypt.TrustManagerImpl.checkServerTrusted(TrustManagerImpl.java:224)
stefan.studmail W/System.err﹕ at com.android.org.conscrypt.Platform.checkServerTrusted(Platform.java:113)
stefan.studmail W/System.err﹕ at com.android.org.conscrypt.OpenSSLSocketImpl.verifyCertificateChain(OpenSSLSocketImpl.java:525)
stefan.studmail W/System.err﹕ at com.android.org.conscrypt.NativeCrypto.SSL_do_handshake(Native Method)
stefan.studmail W/System.err﹕ at com.android.org.conscrypt.OpenSSLSocketImpl.startHandshake(OpenSSLSocketImpl.java:302)
stefan.studmail W/System.err﹕ ... 17 more
stefan.studmail W/System.err﹕ Caused by: java.security.cert.CertPathValidatorException: Trust anchor for certification path not found.
stefan.studmail W/System.err﹕ ... 23 more

Answer 1

Try using Session.getInstance.

If that doesn't help, post the debug output.