Domain is loading the SSL of another unrelated domain

Symptoms​

Attempting to load an SSL returns a different domain website.

Description​

When accessing with https:// a domain that has no SSL installed, the Nginx webserver will automatically serve the SSL of the first domain that it finds on the server. This will result with a SSL warning for the user in browser.

On 'Advanced' you can see that the SSL and domain name does not match:

If ssl is accepted, it will redirect user to the domain that issued SSL.

Workaround​

If you have a domain name set for accessing OpenPanel, then you can set that domain ssl to be used for websites that have no SSL, and if accepted it will die:

nano /etc/nginx/sites-enabled/default

and add the following block but replace server.stefan.rs with your domain and 11.22.33.44 with your server IP address:

server {
    listen 11.22.33.44 :443 ssl http2 default_server;
    server_name _;

    ssl_certificate /etc/letsencrypt/live/server.stefan.rs/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/server.stefan.rs/privkey.pem;

    return 444;
}

Save and restart.

nginx -t && service nginx reload

then when user accepts the SSL it will show an error: