.unicorn.sock failed (111: Connection refused) while connecting to upstreamのエラー

Question

達成したい事

railsで作ったアプリをAWSでデプロイしたい。

起きている問題

unicorn、nginx、mysql全て立ち上がっているのに、サイトに何も表示されない。
それぞれのエラーログを確認したところnginxに出ている

*595 connect() to unix:/var/www/rails/tempo/tmp/sockets/.unicorn.sock failed (111: Connection refused) while connecting to upstream
が原因かと思われる。

エラー文

2021/04/25 02:10:35 [error] 20882#0: *550 open() "/usr/share/nginx/html/GponForm/diag_Form" failed (2: No such file or directory), client: 65.100.24.78, server: _, request: "POST /GponForm/diag_Form?images/ HTTP/1.1", host: "127.0.0.1:80"
2021/04/25 03:53:47 [error] 20882#0: *557 open() "/usr/share/nginx/html/robots.txt" failed (2: No such file or directory), client: 77.88.5.126, server: _, request: "GET /robots.txt HTTP/1.1", host: "staging.coinhack.jp"
2021/04/25 09:43:47 [error] 20882#0: *594 open() "/usr/share/nginx/html/robots.txt" failed (2: No such file or directory), client: 66.249.71.91, server: _, request: "GET /robots.txt HTTP/1.1", host: "staging.coinhack.jp"
2021/04/25 09:47:50 [error] 20882#0: *595 connect() to unix:/var/www/rails/tempo/tmp/sockets/.unicorn.sock failed (111: Connection refused) while connecting to upstream, client: 184.105.247.252, server: 13.231.15.201, request: "GET / HTTP/1.1", upstream: "http://unix:/var/www/rails/tempo/tmp/sockets/.unicorn.sock:/", host: "xx.xx.xx.xxx(伏せてます)"

考えられる原因

• ソケットのパスが間違えている
• nginx.cnfの記述が何かしらおかしい
• インスタンスのユーザー指定が間違えている？

→アクセスキーIDとシークレットアクセスキーIDはインスタンスを立ち上げたユーザとは別ユーザーだから？ただ、アクセスキーIDとシークレットアクセスキーIDを使用したIAMにはAmazonRoute53FullAccessやAmazonEC2FullAccess、AmazonS3FullAccessの権限をつけている

[/etc/nginx/conf.d/tempo(アプリ名).conf]

# log directory
error_log  /var/www/rails/tempo/log/nginx.error.log;
access_log /var/www/rails/tempo/log/nginx.access.log;
# max body size
client_max_body_size 2G;
upstream app_server {
  # for UNIX domain socket setups
  server unix:/var/www/rails/tempo/tmp/sockets/.unicorn.sock fail_timeout=0;
}
server {
  listen 80;
  server_name xx.xxx.xx.xxx(伏せています);
  # nginx so increasing this is generally safe...
  keepalive_timeout 5;
  # path for static files
  root /var/www/rails/tempo/public;
  # page cache loading
  try_files $uri/index.html $uri.html $uri @app;
  location @app {
    # HTTP headers
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header Host $http_host;
    proxy_redirect off;
    proxy_pass http://app_server;
  }
  # Rails error pages
  error_page 500 502 503 504 /500.html;
  location = /500.html {
    root /var/www/rails/tempo/public;
  }
}

unicorn.conf.rb

# set lets
  $worker  = 2
  $timeout = 30
  $app_dir = "/var/www/rails/tempo" #自分のアプリケーション名
  $listen  = File.expand_path 'tmp/sockets/.unicorn.sock', $app_dir
  $pid     = File.expand_path 'tmp/pids/unicorn.pid', $app_dir
  $std_log = File.expand_path 'log/unicorn.log', $app_dir
  # set config
  worker_processes  $worker
  working_directory $app_dir
  stderr_path $std_log
  stdout_path $std_log
  timeout $timeout
  listen  $listen
  pid $pid
  # loading booster
  preload_app true
  # before starting processes
  before_fork do |server, worker|
    defined?(ActiveRecord::Base) and ActiveRecord::Base.connection.disconnect!
    old_pid = "#{server.config[:pid]}.oldbin"
    if old_pid != server.pid
      begin
        Process.kill "QUIT", File.read(old_pid).to_i
      rescue Errno::ENOENT, Errno::ESRCH
      end
    end
  end
  # after finishing processes
  after_fork do |server, worker|
    defined?(ActiveRecord::Base) and ActiveRecord::Base.establish_connection
  end