Hi There are a number of different things to consider with this depending on level of comfort you have with the perceived risk. As a first step, you may wish to get in touch with the owners of the site and see if they can update their certificate. Further to the issue around an out of date certificate, you may also occur if your computer clock has the wrong date. To fix the problem, set your system clock to today's date and time (double-click the clock icon on the Windows Taskbar). Assuming you have done this and are comfortable with the risk of proceeding, if you select the option "I understand the risks" you should be able to proceed to the web page. You can see further information about all of this [https://support.mozilla.org/en-US/kb/connection-untrusted-error-message here]. I hope this helps, but if not please come back here and we can look into a different solution for you.