when attempting to login in to the control panel vi www.website.com/admin I get the login screen and after entering login and password it returns to the same page.

I have searched through the help comments and after refreshing my German can't find a solution. PHP does work on this website as I created a test php page and it works.

the website is www.jaynediller.com

there is no error displayed. If I use a bad password or login i do get the warning.