I am trying to login to our company jabber server using kerberos based login, e.g.

   ConnectionConfiguration config = new ConnectionConfiguration("jabber", 5222);
    config.setSASLAuthenticationEnabled(true);
    config.setDebuggerEnabled(true);
    config.setReconnectionAllowed(true);

    XMPPConnection connection = new XMPPConnection(config);
    connection.getSASLAuthentication().registerSASLMechanism("GSSAPI",SASLGSSAPIMec hanism.class);
    connection.connect();
    connection.login("shahbhat", "", "Smacktest");

With gss.conf of

com.sun.security.jgss.initiate {
com.sun.security.auth.module.Krb5LoginModule required doNotPrompt=true useTicketCache=true;
};

But I am getting

GSSException: No valid credentials provided (Mechanism level: Failed to find any Kerberos Ticket)
    at sun.security.jgss.krb5.Krb5InitCredential.getInstance(Krb5InitCredential.java:1 33)
    at sun.security.jgss.krb5.Krb5MechFactory.getCredentialElement(Krb5MechFactory.jav a:72)
    at sun.security.jgss.GSSManagerImpl.getCredentialElement(GSSManagerImpl.java:149)
    at sun.security.jgss.GSSCredentialImpl.add(GSSCredentialImpl.java:389)
    at sun.security.jgss.GSSCredentialImpl.<init>(GSSCredentialImpl.java:60)
    at sun.security.jgss.GSSCredentialImpl.<init>(GSSCredentialImpl.java:37)
    at sun.security.jgss.GSSManagerImpl.createCredential(GSSManagerImpl.java:96)
    at sun.security.jgss.GSSContextImpl.initSecContext(GSSContextImpl.java:178)
    at sun.security.jgss.GSSContextImpl.initSecContext(GSSContextImpl.java:158)
    at com.sun.security.sasl.gsskerb.GssKrb5Client.evaluateChallenge(GssKrb5Client.jav a:155)
    at org.jivesoftware.smack.sasl.SASLMechanism.authenticate(SASLMechanism.java:118)
    at org.jivesoftware.smack.sasl.SASLGSSAPIMechanism.authenticate(SASLGSSAPIMechanis m.java:86)
    at org.jivesoftware.smack.SASLAuthentication.authenticate(SASLAuthentication.java: 308)
    at org.jivesoftware.smack.XMPPConnection.login(XMPPConnection.java:395)
    at Driver.main(Driver.java:49)
Exception in thread "main" SASL authentication failed:
  -- caused by: javax.security.sasl.SaslException: GSS initiate failed [Caused by GSSException: No valid credentials provided]
    at org.jivesoftware.smack.sasl.SASLMechanism.authenticate(SASLMechanism.java:125)
    at org.jivesoftware.smack.sasl.SASLGSSAPIMechanism.authenticate(SASLGSSAPIMechanis m.java:86)
    at org.jivesoftware.smack.SASLAuthentication.authenticate(SASLAuthentication.java: 308)
    at org.jivesoftware.smack.XMPPConnection.login(XMPPConnection.java:395)
    at Driver.main(Driver.java:49)
Nested Exception:
javax.security.sasl.SaslException: GSS initiate failed [Caused by GSSException: No valid credentials provided]
    at com.sun.security.sasl.gsskerb.GssKrb5Client.evaluateChallenge(GssKrb5Client.jav a:174)
    at org.jivesoftware.smack.sasl.SASLMechanism.authenticate(SASLMechanism.java:118)
    at org.jivesoftware.smack.sasl.SASLGSSAPIMechanism.authenticate(SASLGSSAPIMechanis m.java:86)
    at org.jivesoftware.smack.SASLAuthentication.authenticate(SASLAuthentication.java: 308)
    at org.jivesoftware.smack.XMPPConnection.login(XMPPConnection.java:395)
    at Driver.main(Driver.java:49)
Caused by: GSSException: No valid credentials provided
    at sun.security.jgss.GSSCredentialImpl.<init>(GSSCredentialImpl.java:69)
    at sun.security.jgss.GSSCredentialImpl.<init>(GSSCredentialImpl.java:37)
    at sun.security.jgss.GSSManagerImpl.createCredential(GSSManagerImpl.java:96)
    at sun.security.jgss.GSSContextImpl.initSecContext(GSSContextImpl.java:178)
    at sun.security.jgss.GSSContextImpl.initSecContext(GSSContextImpl.java:158)
    at com.sun.security.sasl.gsskerb.GssKrb5Client.evaluateChallenge(GssKrb5Client.jav a:155)

Any idea how to fix this error, thanks.