使用nginx / 1.14.0的502错误网关（Ubuntu）

Question

我一直在尝试使用Ubuntu 18.04实例从Amazon Web Services部署我的网站。我遵循了本文档中的所有步骤：https://medium.com/@rksmith369/how-to-deploy-mern-stack-app-on-aws-ec2-with-ssl-nginx-the-right-way-e76c1a8cd6c6。而不是查看我的项目，我收到502 Bad Gateway错误。我尝试修复此文件：/ etc / nginx / sites-available

server {
    listen 80;
    index index.html
    root /var/www/facemusic;
    location / {
        proxy_pass http://172.31.93.58:3001;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection 'upgrade';
        proxy_set_header Host $host;
        proxy_cache_bypass $http_upgrade;
    }
}

我还键入了nginx -t来测试nginx服务器并发现以下错误：

nginx: [warn] the "user" directive makes sense only if the master process runs with super-user privileges, ignored in /etc/nginx/nginx.conf:1
nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
nginx: [emerg] open() "/run/nginx.pid" failed (13: Permission denied)
nginx: configuration file /etc/nginx/nginx.conf test failed

我已经在Google上搜索了几个小时，但仍然无法弄清。