Take a look at the message? see screenshot What are your settings? Post a screenshot of your settngs. The site works for me, see my security settings. see screenshot Did you try with Firefox in Troubleshoot Mode? What OS? If windows, what security software are you running? If Windows Pro version, try testing in Windows Sandbox (VM) to see if you have the same issue. https://www.howtogeek.com/399290/how-to-use-windows-10s-new-sandbox-to-safely-test-apps/

I tried with protection settings completely off and still got the same issue. Tried with troubleshoot mode and couldn't find anything helpful. Windows 10 home unfortunately. Will need to check on the security software running, but it is strange because it opens just fine on other web browsers.

We'll leave the light on for ya.  ;-))