Wrong subdomain redirects to other subdomain

When I try to connect to wrong url (e.g.: abc.seoulsaram.org) it shows ssl warning but if I ignore it. It redirects to the other my subdomain website.

It's happening both wildcard and non-wildcard cert.

It might not be the nginx configuration problem.

My domain is: seoulsaram.org

I ran this command: curl -k abc.seoulsaram.org

It produced this output:
output of my other website

My web server is (include version): nginx/1.18.0

The operating system my web server runs on is (include version): Debian 11

My hosting provider, if applicable, is: Vultr

I can login to a root shell on my machine (yes or no, or I don't know): Yes

I'm using a control panel to manage my site (no, or provide the name and version of the control panel): No, with ssh

The version of my client is (e.g. output of certbot --version or certbot-auto --version if you're using Certbot): certbot 1.12.0

Hello @dd_d ,welcome to the Let's Encrypt community. :slightly_smiling_face:

For general nginx information, such as redirects, please see nginx documentation and https://forum.nginx.org/ .

Here is an online tool to help check redirects https://www.redirect-checker.org/

This is the certificate presently being served https://decoder.link/sslchecker/abc.seoulsaram.org/443

Common Name: 	seoulsaram.org
                Total number of SANs: 6

None of the SANs match abc.seoulsaram.org

Kindly wait to see if there are more knowledgeable Let's Encrypt community volunteers willing to assist.