Nginx 反向代理504 Gateway Time-out

location /ssfwpt {
                        proxy_set_header  X-Real-IP  $remote_addr;
                        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
                        proxy_set_header Host $http_host;


                        proxy_connect_timeout           300;
                        proxy_send_timeout              300;
                        proxy_read_timeout              300;

                        proxy_pass http://xxxx;
                }