502 Error Fresh NGINX Installation

Wordpress Version: Latest
OS: Debian 10
PHP: 7.4
NGINX: 1.14.2

WordPress files are at /var/www/wordpress, level 775 permissions owned by www-data:www-data recursively on the directory and its sub-directories, NGINX has been configured as follows:

sudo unlink /etc/nginx/sites-enabled/default

sudo ls -s /etc/nginx/sites-available/t20.digital /etc/nginx/sites-enabled/t20.digital

virtual host file at /etc/nginx/sites-available/t20.digital reads as follows:

upstream php {
    server unix:/tmp/php-cgi.socket;
    server 127.0.0.1:9000;
}

server {
    server_name t20.digital;
    root /var/www/wordpress;
    index index.php;
    
    location = /favicon.ico {
        log_not_found off;
        access_log off;
    }
    
    location = /robots.txt {
        allow all;
        log_not_found off;
        access_log off;
    }
    
    location / {
        try_files $uri $uri/ /index.php?$args;
    }
    
    location ~ \.php$ {
        include fastcgi_params;
        fastcgi_intercept_errors on;
        fastcgi_pass php;
        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
    }
    
    location ~* \.(js|css|png|jpg|jpeg|gif|ico)$ {
        expires max;
        log_not_found off;
    }
}

NGINX config is setup exactly as per NGINX Documentation reccomends, NGINX returns 502 bad gateway when accessing the server via https://ip

Support hugely appreciated!