DNS or caching showing the previous host.
FIRST, ESTABLISH WHICH YOU ARE SEEING
Check what the domain resolves to and compare against the address of the new server.
If it resolves to the old address, DNS has not updated.
IF DNS IS STILL OLD
Confirm the nameservers were changed at the registrar, not only in a DNS zone.
Check the registrar directly. A change made in the wrong place appears done and is not.
Propagation takes up to forty-eight hours, though usually far less.
IF DNS IS CORRECT AND YOU STILL SEE THE OLD SITE
Your own device is caching. Try a private window, another browser, and mobile data.
Flush your local DNS cache.
TESTING BEFORE DNS CHANGES
A hosts file entry points your machine at the new server while everyone else still reaches the old one.
That is how to verify a migration before switching.
DO NOT CANCEL THE OLD HOSTING
Until the new one is verified and propagation is complete. A week is a sensible minimum.
