Nginx抛出502

Question

以下nginx.conf会抛出一个常量502错误：

server {
    listen 80;

    server_name mydomain.com;

    index index.php index.html index.htm;

    set $root_path '/home/forge/mydomain.com/public';
    root $root_path;

    try_files $uri $uri/ @rewrite;

    location @rewrite {
        rewrite ^/(.*)$ /index.php?_url=$1;
    }

    location ~ \.php {
        fastcgi_pass unix:/run/php-fpm/php-fpm.sock;
        fastcgi_index /index.php;

        include /etc/nginx/fastcgi_params;

        fastcgi_split_path_info       ^(.+\.php)(/.+)$;
        fastcgi_param PATH_INFO       $fastcgi_path_info;
        fastcgi_param PATH_TRANSLATED $document_root$fastcgi_path_info;
        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
    }

    location ~* ^/(css|img|js|flv|swf|download)/(.+)$ {
        root $root_path;
    }

    location ~ /\.ht {
        deny all;
    }
}

我直接从Phalcon网站上得到了这个，但这引发了一个错误。我查看了我的服务器日志，我发现了这个错误：connect() to unix:/run/php-fpm/php-fpm.sock failed (2: No such file or directory) while connecting to upstream。我对Nginx的了解太少，无法确切知道这里出了什么问题。做你们中的任何一个吗？