Things Engraved has investigated some issues related to Proxy Servers not properly supporting TLS v1.1+. In these scenarios, when attempting to visit our Secure Website Content, the Proxy Server will generate a 'Web Protection' page suggesting that the website cannot be reached. Usually these pages will also show a software Vendor Name, different from the Browser's Vendor Name, giving an indication that the browser is not responsible for the issue. In these cases, you will need to work with the Proxy Server vendor, or those responsible for the Proxy Server installation, in order to have the issue resolved.
As a simple test, attempting to reach here should present you with a page showing your Internet IP Address. If it does not, then there may be a Proxy Server preventing you from reaching Secure Content on our Website. If you have an IT Group that is responsible for Security Software on your computer, you may need to contact them, and ask for support.