When I first clicked http://demo.phpmyadmin.net it worked fine. Now http://demo.phpmyadmin.net is a redirect loop (last page is http://demo.phpmyadmin.net////////////). Maybe the page that was displayed when I first clicked was cached.Also, all links on https://www.phpmyadmin.net/try/ lead to redirect loops:etc.Using incognito did not help (which is equivalent to clearing data). This testing was done on Google Chrome.
On Firefox everything works fine even after multiple refreshes.