I search all over website,
it said problem with clear caches and delete all private data... etc!
One forum it said "try to log-in, by itself" (hotmail).
AND
Log it out successful...
What I learn?
Options=>Accounts=>[uncheck] Keep session for links
For some reason I did click [X] Keep session for links... long, long time ago.
I have no problem log it out,
until a couple of months,
and when UNcheck and it WORKS GREAT!
As Tobwithu's explain about Keep session for links.