[Samba] How to verify the domain secret is good or bad?

[Chere Zhou]

I know there is the command "wbinfo -t".  But when it says that "could not 
check secret", how do I know it's the secret is bad, or something else wrong, 
like winbind went crazy maybe?  

Also, sometimes I saw problems like "wbinfo -t" just says "secret is bad", 
when all the daemons were running.  It sure was good at some point before.  

So my question is, in what condition that the secret can go bad?  How do I 
check it?

Thanks in advance.

Chere