Make sure that you are trying to access the UK version of Blue Castle.
Try closing your browser completely and clearing your history/cache then reopen the browser.
On a PC use the appropriate menu (Tools in Internet Explorer and Firefox, main menu in Chrome, settings menu on an iPad).
If the problem persists contact Digital and Technical Services by phone: +44 (0)115 95 16677 (Mon-Fri 8-4pm), or by log the issue through the Self-Service Portal.