DNS propagation is a period of time in which it takes updates to DNS records to be in full effect over all of the servers on the web. The reason changes aren’t immediate is because nameservers save domain record data in their cache memory for a particular amount of time before they refresh. So while your domain won’t experience any downtime from well-planned record changes, some users will still be served a cached version of your website until all servers have propagated.
Usually, DNS propagates within a few hours, but it can take as long as 72. The time for propagation is based on different factors, such as your internet service provider (ISP), your domain’s registry, and the TTL values of your DNS records. Learn more interesting information about DNS propagation and how to check it!