Firefox doesnt signout properly

Hello,

we installed a 3rd party application and noticed FF doesnt signout properly.

CASE

1. If i signin afresh with FF, everything works ok with both our local application and the 3rd party app

2. When I signout, and sign in again. The 3rd party application doesnt sign

When i check the cookies in FF, I See the cookies are still there. Here is my signout code

 

        Session.Abandon();
        FormsAuthentication.SignOut();
        FormsAuthentication.SignOut();
        Roles.DeleteCookie();
        Session.Clear();

 

Is there other ways of flushing out all the cookies ?

thanks
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