problems with staying logged in

[traily]

we did an upgrade to 3.8.6 and since then we get logged out and it doesnt remember username in the 'remember me'

i went into vbulletin option in the CP then cookies and http header options and change the top window from 900 seconds to 4000, but it doesnt appear to be the right one

anyone suggest a fix?

thanks

[traily]

gee i thought this was a simple question...
no one has any idea why this is happening? or have i asked the question in the wrong section or something?