The reason you’re unable to access your website is because of something called DNS Caching, also called DNS Propagation.
In short, it’s a consequence of your network settings, and who will be able to access your site and who won’t is a consequence of their network settings. Nobody can guarantee that your website will work on every device on every network in the world.
If it’s not working for you, you can try to clear your browser’s DNS cache. If that doesn’t solve it, the bad data is cached by your configured DNS resolvers. You can work around that by configuring your computer to use faster resolvers, such as Google Public DNS or Cloudflare’s 1.1.1.1 service: