title: 502 Bad Gateway nginx/1.10.3 (Ubuntu)
body: <p>Trying to deploy an application written in Rails and Angular.</p>
  
  <p>I am getting 502 gateway timeout error in browser when i was sending the request through browser</p>
  
  <p>when i checked the logs , i got this error:</p>
  
  <pre><code>2017/12/17 20:07:48 [error] 12347#12347: *1 connect() failed (113: No route to host) while connecting to upstream, client: 10.50.60.2, server: 10.12.4.245, request: "GET /favicon.ico HTTP/1.1", upstream: "http://10.12.4.245:80/favicon.ico", host: "10.12.4.242", referrer: "http://10.12.4.242/"
  </code></pre>
  
  <p>How can I fix it and please explain in detail.</p>
  
  <p>Here is my configuration:</p>
  
  <p>/etc/nginx/sites-available/nginx.conf:</p>
  
  <pre><code> upstream puma {
    server unix:///var/www/phonebook-api/tmp/sockets/puma.sock;
  }
  server {
  listen   80 default;
  listen   [::]:80 default ipv6only=on;
  
  server_name 10.12.4.245;
  charset utf-8;
  root /var/www/phonebook-api;
  
    access_log /var/log/nginx/access.log;
    error_log /var/log/nginx/error.log;
  
  location / {
  root phonebook-app/dist;
  index index.html index.htm;
  try_files $uri @app;
          gzip_static on;
          expires max;
          proxy_read_timeout 150;
          add_header Cache-Control public;
    }
    try_files $uri/index.html $uri @puma;
    location @puma {
      proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
      proxy_set_header Host $http_host;
      proxy_redirect off;
      proxy_pass http://puma;
    }
     location @app {
       proxy_pass        http://10.12.4.245;
       proxy_set_header  X-Real-IP  $remote_addr;
       proxy_set_header  X-Forwarded-For $proxy_add_x_forwarded_for;
       proxy_set_header  X-Forwarded-Proto http;
       proxy_set_header  Host $http_host  ;
       proxy_redirect    off;
       proxy_next_upstream error timeout invalid_header http_502;
      }
  
    client_max_body_size 50M;
    keepalive_timeout 10;
  }
  </code></pre>