Connection refused Nginx

As I am trying to install a Droplet with LEMP and running my Laravel Project on it. It gives me a 502 Bad Gateway then I went to the log file and saw this error:

2021/08/01 11:30:17 [error] 29534#29534: *13 connect() failed (111: Connection refused) while connecting to upstream, client: MY_IP_ADDRESS, server: DOMAIN_NAME, r>

My config file looks like these:

    server_name DOMAIN_NAME;
    root /var/www/DOMAIN_NAME/public;

    add_header X-Frame-Options "SAMEORIGIN";
    add_header X-Content-Type-Options "nosniff";

    index index.php;

    charset utf-8;

    location / {
        try_files $uri /index.php?$query_string;
    }

    location = /favicon.ico { access_log off; log_not_found off; }
    location = /robots.txt  { access_log off; log_not_found off; }

    error_page 404 /index.php;

    location ~ .php$ {
       root /var/www/DOMAIN_NAME/public;
       fastcgi_split_path_info ^(.+\.php)(.*)$;
       fastcgi_pass   127.0.0.1:9000;
       fastcgi_index  index.php;
       fastcgi_param  SCRIPT_FILENAME  /var/www/DOMAIN_NAME$fastcgi_script_name;
       include fastcgi_params;
    }

    location ~ /\.(?!well-known).* {
        deny all;
    }
}

Please can someone explain what I am doing wrong here?