Resolving correctly, serving wrongly.
WHAT IT MEANS
DNS is fine. The request reached a server, and that server served something else.
THE COMMON CAUSES
The domain is not added to the account it points at It points at the correct server but the wrong account The document root is wrong A default or holding page is being served An addon domain configured incorrectly
CHECKING
Confirm the address the domain resolves to matches your account's address.
If it does, the problem is on the server, not in DNS.
IF IT SHOWS ANOTHER CUSTOMER'S SITE
The domain resolves to a shared address and is not configured on the server, so the default site is served.
Add the domain to your account.
IF IT SHOWS A HOLDING PAGE
Same cause, usually.
IF IT SHOWS YOUR OTHER SITE
Document root or addon domain configuration.
cPanel > Domains shows the path for each.
WHAT TO SEND US
The domain, the address it resolves to, and what appears.
That combination identifies the cause immediately.