Cannot access one website

Using OS 10.6.8, I suddenly cannot access this one website. https://www.wideners.com/ using Safari or Firefox. I also tried IE using my virtual machine with no success. Can be accessed on other PC's and devices.

Get the generic 'can't open the page because can't establish a secure connection.

Any ideas? I notified the owner and all they can tell me is that I may need to update my browser. I don't know what to look for.