example.com is not a registered domain in Cloudflare - Nameservers are your primary DNS controller and identify the location of your domain on the Internet. Domain registrars can take up to 24 hours to process the nameserver updates. You will receive an email from Cloudflare once your site is activated.

example.com is not a registered domain in Cloudflare

If you are also getting this error, then you do not have to take much tension, you just have to wait for 24 hours, because your domain has been bought just a few hours ago, so it takes time to register it on TLD Server. |

When you add your domain per 24 Hour After Cloudflare then you are successful.