Domain Not Pointed to Server Properly

Hello! I'm completely new to all this web hosting stuff, so bear with me. I used a .tk domain. When I input the domain into the web hosting service, I then updated the nameservers. But when I try and access my server through the domain, I get an error from Firefox saying they can't connect to the server. How do I get this working? The server hoster on discord said that international domains aren't supported. Is .tk an international domain? How would I change my primary domain to another domain such as a .club or .xyz? I do have a shared IP address if that helps at all. Thank you!