Why do some clients receive content not from their unique server names but from a common name when using virtual shared hosting?

In virtual shared hosting, multiple websites are hosted on a single server with one IP address. The web server (e.g., Apache or Nginx) uses virtual host mechanisms to serve the correct content based on the requested host name (Host header in HTTP).

If a client receives content not from its unique server name but from a common name, it could be due to several reasons:

• Incorrect virtual host configuration: the server does not recognize the host name and serves default content.
• DNS records are not configured correctly, and requests are directed to a shared address.
• Caching on the client side or proxy may serve outdated or shared content.
• Using an IP address instead of a host name in the request.

Therefore, it is important to correctly configure DNS, virtual hosts, and ensure that requests contain the correct Host header.