From visitor to server.
WHAT HAPPENS
The visitor's device resolves your domain to an address It connects to that address The web server identifies which site is requested It responds
WHAT THE SECOND STEP DEPENDS ON
Your A record pointing at the correct server.
WHAT THE THIRD STEP DEPENDS ON
The server knowing that domain belongs to an account.
WHY BOTH MATTER
A correct A record pointing at a server that does not recognise the domain produces an error, not your site.
WHAT THAT EXPLAINS
Adding a domain to DNS but not to the hosting account, and seeing the wrong site or an error.
HOW SEVERAL SITES SHARE ONE ADDRESS
The request includes the name requested.
The server uses it to select the correct site.
WHAT THAT MEANS
An address alone does not identify a site.
WHY THAT MATTERS FOR TESTING
Visiting the server address directly does not show your site.
Use a hosts file entry instead, to test before changing DNS.
