After you register a domain or change its nameservers, the update can take up to 24 to 48 hours to reach everyone, though it is often much faster.
While you wait, try a private browser window or another device. On Windows, you can also clear your computer's saved address information by opening Command Prompt and typing ipconfig /flushdns.
If the site still is not showing after 48 hours, open a support ticket.
