If you change any domain name server, it will take a few hours to reflect globally. This is called DNS propagation. It usually takes 12 to 24 hours.
Whenever your website is accessed via an ISP network, it stores a copy of this domain DNS. Once the name server has been changed or updated, it will take a while to clear the old copy and store a new copy of the DNS resolver. We recommend changing the name server as long as the site has a minimal amount of traffic.
You can check global propagation from this URL. https://www.whatsmydns.net
