The site does not open by domain: what to check yourself

The page opens by IP and not by the domain. Or it opens someone else's site, or the browser says the name was not found. Four checks usually answer that before you write to support.

Which name servers the registrar has

Look at the NS records set at the domain registrar. A and AAAA records only work on the name servers the domain actually uses. Editing the zone in the wrong place changes nothing for visitors.

Where the name itself points

The A record should point at the IP of your VPS or hosting. www needs the same record, or a CNAME to the main name. A common picture: the bare domain opens and www does not, or the other way around. Check both names.

How long it has been

After you change NS or A, the record does not spread at once. A few minutes to a few hours is typical. If a day has passed and DNS still returns the old answer, the zone was edited on the wrong NS, or the record has a typo.

The certificate and the browser's memory

If the name already points at your IP and the browser complains about the certificate, the request reached the server. You need a certificate for this exact domain, including www if you use it. Close the old tab before you try again: the browser remembers both the error and the redirect.

When you do write to support, include the facts: which NS the registrar has, which IP the A record returns, and what the browser shows. That is faster than "the domain does not work".