Reuven, I'm not having any of that kind of trouble. I successfully log in the very first time and stay logged in. I do log out when I'm finished testing things. I also have the settings set in IE 11 where it will clear the cache and cookies once I exit out of IE 11.
I wonder if clearing the cache and cookies would help. It might also depend on which browser is being used.
Just adding that I use the same password as I do here when I log in.