PLAIN SASL Authentication failed with smack 3.0.2

I get the following SASL exception while trying PLAIN SASL mechanism with smack 3.0.2. Any suggestions?

SASL authentication failed:

at org.jivesoftware.smack.SASLAuthentication.authenticate(SASLAuthentication.java: 205)

at org.jivesoftware.smack.XMPPConnection.login(XMPPConnection.java:341)

Have you setup java on your client to know about your Kerberos realm, KDC etc?

When using a client, I usually get that error if the client’'s not aware of the KDC it should be talking to or when there is no reverse DNS lookup for identifying service principal name.