Work through these in order.
1. IS IT REGISTERED AND CURRENT?
Look it up in WHOIS. Check the expiry date. An expired domain is the most common cause and produces exactly this symptom while hosting is untouched.
2. ARE THE NAMESERVERS CORRECT?
WHOIS shows the current nameservers. Compare them with the pair for your account in Services > My Services. Wrong pair, or the old host's still in place, means it will never resolve here.
3. HAS ENOUGH TIME PASSED?
Nameserver changes take from an hour to 24 hours. Check with an external propagation tool rather than your own browser.
4. DOES THE ZONE HAVE AN A RECORD?
If nameservers are right but nothing loads, check the A record in cPanel > Zone Editor, or at your external DNS provider if that is where records live.
5. IS IT ONLY YOU?
Test from mobile data with wifi off. If it loads there, your IP has been blocked by the firewall. Open a ticket with your address.
6. IS THE ACCOUNT SUSPENDED?
Check Services > My Services and your email.
Still stuck: open a ticket with the domain name and the results of these checks.
