Since I upgraded to version 7.5.7 cookies for returning members are not working any more. Logged in users stay logged in during their session, but once they close their browser, they are logged out. I tried re-uploading the changed 7.5.7 files, deleting my cookies and saved passwords, but nothing seems to work. Do you have any suggestions how to make this work again?

By the way: I had complains about this from IE, Firefox and Chrome users.