A domain name server change will take a few hours to propagate globally. This is called DNS propagation. It usually takes 12-24 hours.
When you access your website through an ISP network, the ISP stores a copy of the Domain DNS. When the nameservers change, it takes time to wipe out the old copies and store a new copy of the DNS resolver. Therefore, we recommend changing the nameservers when your website has the lowest traffic possible.
This URL will show you the DNS propagation status.
