The name goes nowhere.
WHAT TO CHECK IN ORDER
Is the domain expired? Where do the nameservers point? Do the DNS records exist? Has enough time passed since a change?
THE EXPIRY CHECK FIRST
An expired domain resolves nowhere, and nothing else will help.
THE NAMESERVER CHECK
If they point at another provider, records must be managed there.
Changing them takes time to take effect.
THE RECORD CHECK
An A record must point at the server address.
FOR A SUBDOMAIN
Creating it in cPanel is sufficient only if the domain uses our nameservers.
With external DNS, the record must also be added there.
That is a common and confusing failure.
FOR A RECENT CHANGE
Propagation takes time, and your own device may cache the old record.
Check from mobile data to bypass local caching.
FOR A NEW DOMAIN
Some registrations take time to become active.
WHAT TO DO IF EVERYTHING LOOKS CORRECT
Open a ticket with the domain and what you have checked.