If a user fails to login using SASL the only thing that appears in the log is below:
org.jivesoftware.openfire.net.SASLAuthentication - User Login Failed. Failure to initialize security context
This could be due to a number of different things. The main one I am aware of is just DNS, but my openfire DNS is set up fine, I have perthim.smy.local as an A record to 192.168.60.20 and I have a PTR from 192.168.60.20 to perthim.smy.local. The domain and fqdn server properties are both set to perthim.smy.local.