浏览器无法访问Mojolicious Hypnotoad Nginx反向代理

Question

应用程序正在服务器中运行。但是无法从浏览器访问它。

示例配置文件 -

server {
  listen [::]:80;
  server_name ..;
  access_log /var/log/..;
  error_log /var/log/..;

  location / {
    proxy_pass http://localhost-app;
    proxy_http_version 1.1;
    proxy_read_timeout 150s;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection "upgrade";
    proxy_set_header Host $host;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header X-Forwarded-HTTPS 0;
  }
}

upstream localhost-app {
  server 127.0.0.1:8081;
}

nginx版本：nginx / 1.10.3

Ubuntu 16.04.3 LTS