You changed the DNS record.
You checked it twice.
But your website still points to the old server.
What happened?
Usually, nothing is wrong.
DNS changes can take time to propagate because different systems may cache DNS information.
DNS Isn't a Single Database
When you change a record, the entire internet doesn't instantly receive the new value.
Different resolvers can continue using cached information until the record's TTL expires.
That's why two people can sometimes see different results temporarily.
TTL Controls Caching
TTL means Time to Live.
It tells DNS resolvers how long they can cache a record.
A longer TTL can reduce DNS lookup traffic.
A shorter TTL can make planned changes easier to switch over.
Plan Important Migrations
If you're moving a production website to another server, don't wait until the migration day to think about DNS.
Lowering the TTL ahead of time can make the eventual switch easier.
But remember:
Changing TTL doesn't instantly erase existing cached records.
The old TTL needs to expire first.
Check More Than Your Own Computer
If you've changed DNS, test from different networks or DNS lookup tools.
Your computer may still have cached information.
Your internet provider may have cached information too.
DNS Problems Can Look Like Hosting Problems
A perfectly healthy application can appear offline if the domain points to the wrong destination.
That's why troubleshooting should include:
DNS records Domain configuration SSL Server status Application status
When a domain isn't working, don't immediately blame the server. Check where the domain is actually pointing.