Nginx中多个端口中的多个应用程序无法正常工作

Question

Nginx配置文件如下：

仅加载honfronend时出现问题，但honbackend却不起作用：

前端配置

 upstream honfronend {
        # Nodejs app upstream
        server 127.0.0.1:5000;
        keepalive 64;
    }

后端配置

 upstream honbackend{
        server 127.0.0.1:3000; 
    }

端口80上的服务器

server {
    listen 80;
    server_name www.honeygram.com;
    root /var/apps/hgweb;

    location / {
        # Proxy_pass configuration
        proxy_pass http://honfronend/;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header Host $http_host;
        proxy_set_header X-NginX-Proxy true;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "upgrade";
        proxy_max_temp_file_size 0;
        proxy_redirect default;

   }

}
server {
    listen 81;
    server_name api.honeygram.com;
    server_tokens off;
    root /var/apps/HGBackend;

    location /api/ {
      proxy_pass http://honbackend;
      proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
      proxy_set_header Host $http_host;
      proxy_set_header X-NginX-Proxy true;
      proxy_set_header X-Ssl on;
      proxy_redirect default;
    }


}

hgbackend出现以下错误

404 Not Found
nginx

那我应该怎么办？