Everything was working just fine. To fine tune security I have turned off “shared sessions” - the system has logged me out and on attempt to log in it tells me that the webmaster has forbidden my access - while my access is the only one to the backend. Front end fortunately works.
It's odd you get access only to backend as you should have been blocked for the entire site. Did you try cleaning your browser's cache to access your backend?
If you are still blocked please reply to this email and I will contact you privately to unblock you.