It is not an issue on your side, Buta. The error is coming from the site. The team only needs to renew their SSL certificate, which isn't hard to do.

Someone's still paying for site hosting, but I guess you'll find out for sure on whether or not it has been abandoned sometime after May 26, 2020, when the domain's current registration ownership expires. They have to renew it around then for you to either continue seeing what you do now, or for them to begin offering some updated set of services from that URL.

Whether it's there or not won't make much of a difference for the future of this coin, but I do hope they keep it around since you remember it working for you as well as it did.