Hi there @parmarjatin834,

It is possible that the other domain name is also pointing to your server’s IP address.

To check that you could use the following DNS lookup tool:

https://www.digitalocean.com/community/tools/dns

If the A record of the strange domain name matches your website, what you could do is add a separate virtual host for your domain name and then create a default virtual host to catch all other traffic and not show your website.

Here is a tutorial on how to add a virtual host to your Nginx webserver:

https://www.digitalocean.com/community/tutorials/how-to-set-up-nginx-server-blocks-virtual-hosts-on-ubuntu-16-04

Regards,
Bobby