Working fine for me, tested EU / NA with ENa nd DE languages. No certificate warnings or similar.
e.g.
https://us.tamrieltradecentre.com/pc/Trade
or
https://eu.tamrieltradecentre.com/pc/Trade
Tested with 3 browsers. Chrome, Edge and Firefox. All without any addons/plugins/enhancements enabled.
Maybe your ISP got issues or your browser's enhancements/plugins block something? Or your Antivirus does.
Try to whitelist the site in your tools.
The only prob I have with that site is that every time I check it for triune jewelry at affordable costs so I can finally research that trait, it's all sold out before I can get to the seller.
It needs an alert system.