Nginx Proxy – How to Configure proxy_pass to HTTPS

So I would like to proxy_pass requests to an https backend server, however, every time I try to reload nginx server with https:// configured backend I get the following error:

nginx: [emerg] https protocol requires SSL support

This is the nginx config

server{

    listen 8080;

    root /opt/nginx_1.17.0/nginx_ok/html;
    server_name www.frontedndomain.com;

    index index.php index.html;

            location /health-monitor/ {
                    add_header Custom-Header test;
            }

            location ~* ^\/([a-z][a-z]\/)?abc\/?(.*)? {
                    error_log /opt/nginx_1.17.0/nginx_ok/logs/proxy_error.log;
                    add_header X-query-string $is_args$query_string;
                    resolver 0.0.0.0;
                    resolver_timeout 15s;
                    proxy_pass https://backenddomain.com;
                    proxy_ssl on;
                    proxy_http_version 1.1;
                    proxy_set_header Accept-Encoding "";
                    proxy_set_header Cache-Control no-cache;
                    proxy_set_header Upgrade $http_upgrade;
                    proxy_set_header Connection 'upgrade';
                    proxy_set_header X-Real-IP $remote_addr;
                    subs_filter_types *;
           }
    }

Originally I've built nginx for source and this is the output of nginx -V

nginx version: nginx/1.16.0 built by gcc 4.8.5 20150623 (Red Hat
4.8.5-36) (GCC) configure arguments: –prefix=/opt/nginx_1.17.0/nginx_ok/ –sbin-path=/opt/nginx_1.17.0/nginx_ok/sbin/nginx –with-openssl=/opt/nginx_1.17.0/openssl-1.1.1c/ –add-module=/opt/nginx_1.17.0/ngx_http_substitutions_filter_module/ –with-zlib=/opt/nginx_1.17.0/zlib-1.2.11/

Can someone please outline what I'm missing from this config please. I would like to also forward a query string to the backend.