I'm using Slimjet as my browser (which is basically a somewhat better version of Chrome, which doesn't try to link everything I do to Google). Clicking on links within the site you've pointed me to produces a message saying "This site can’t provide a secure connection".
That means that the website is saying that it's using an 'https' connection, rather than an 'http' one, (which is more secure if, say, you're submitting data to a site) but that it hasn't got a valid security certificate to prove that it really is using 'https'.
As the site was working for you a week ago, that suggests to me that the web administrator has failed to pay for an up-to-date security certificate and that its old one has now expired.
So the problem is 'at their end', rather than at yours. Hopefully the site administrator will fix the problem soon. However there is a workaround available to you, as follows:
Click on the link you want to use.
When you then get to a page that's not responding, look in your browser's address bar to where it says 'https'.
Click to place your cursor immediately to the right of the 's' and then hit your backspace button to delete that character.
Then hit enter.
The page should then load using 'http', rendering the need for a security certificate unnecessary, thus enabling you to view it.