I think it may be related to your browser - I can access it through Firefox but I haven't been able to access it through Chrome for some time. On Chrome as soon as I log in it immediately logs me out.
Best to let the admin know, as they might be totally unaware there is an issue.
Are thay still using free hosting? Since I changed hosts everything here has been much more reliable and with a few exceptions, you do tend to get what you pay for.