I had client of mine contact me this morning about them not being able to login to the CP of the site. I thought at first it was a cookie/session issue, but after having them clear their browser history numerous times, try other browsers, etc., it was doing the same. So I asked for their password and tried locally myself and the same thing was happening, it would just redirect back to the login page. However, I'm able to login since my user is in the Super Admin group. Anyone else experience this before or know of any fixes?