DNS propagation is the process of applying changes to your domain names DNS records throughout the internet. When you make a change to your DNS zone on your domain, whether this is a change to the nameservers or A records, the change needs to be propagated to all servers around the world in order for your domain to work correctly.
The time these changes take to fully propagate throughout the internet can vary between different locations, however, can take up to 24 hours (usually much less) and on very rare occasions can take up to 72 hours.
As the internet is global, during this process, some areas may see different data when visiting a website. This is normal and means that the propagation process has not been fully completed and you simply need to allow a little time for the changes to take effect.
You can check the status of your DNS propagation by using a free tool such as DNSChecker.