症状

rails sでサーバーを起動し、コンソール上では起動してそうな感じだが、locakhost:3000にアクセスしても全く反応しない事象が発生しました。

以下はターミナル

ubuntu:~/environment/hello_app (master) $ rails s
=> Booting Puma
=> Rails 6.0.3 application starting in development 
=> Run `rails server --help` for more startup options
Puma starting in single mode...
* Version 4.3.6 (ruby 2.6.3-p62), codename: Mysterious Traveller
* Min threads: 5, max threads: 5
* Environment: development
* Listening on tcp://127.0.0.1:8080
* Listening on tcp://[::1]:8080
Use Ctrl-C to stop

実施したが解決しなかった対策
・rails server起動しなおし
・adBlockerなどは無効化
・ブラウザの開き直し
・bundle install→updateのやり直し
・rails s -b 0.0.0.0→rails s -b $IP -p $PORT

解決方法

1.「preview」→「previewrunningapplication」で表示させた画面を閉じる
2.再度「previewrunningapplication」開きなおす
3.サーバーを起動下記画像の「Browser」の右側の■を押下

→別タブで「Yay! You’re on Rails!」の画面が開けるようになりました。

以下は成功時のターミナル

ubuntu:~/environment/hello_app (master) $ rails s
=> Booting Puma
=> Rails 6.0.3 application starting in development 
=> Run `rails server --help` for more startup options
Puma starting in single mode...
* Version 4.3.6 (ruby 2.6.3-p62), codename: Mysterious Traveller
* Min threads: 5, max threads: 5
* Environment: development
* Listening on tcp://127.0.0.1:8080
* Listening on tcp://[::1]:8080
Use Ctrl-C to stop
Started GET "/" for 61.215.149.134 at 2021-03-04 14:18:46 +0000
Cannot render console from 61.215.149.134! Allowed networks: 127.0.0.0/127.255.255.255, ::1
   (2.7ms)  SELECT sqlite_version(*)
Processing by Rails::WelcomeController#index as HTML
  Rendering /home/ubuntu/.rvm/gems/ruby-2.6.3/gems/railties-6.0.3/lib/rails/templates/rails/welcome/index.html.erb
  Rendered /home/ubuntu/.rvm/gems/ruby-2.6.3/gems/railties-6.0.3/lib/rails/templates/rails/welcome/index.html.erb (Duration: 13.0ms | Allocations: 479)
Completed 200 OK in 64ms (Views: 27.3ms | ActiveRecord: 0.0ms | Allocations: 2758)


Started GET "/" for 61.215.149.134 at 2021-03-04 14:18:58 +0000
Cannot render console from 61.215.149.134! Allowed networks: 127.0.0.0/127.255.255.255, ::1
Processing by Rails::WelcomeController#index as HTML
  Rendering /home/ubuntu/.rvm/gems/ruby-2.6.3/gems/railties-6.0.3/lib/rails/templates/rails/welcome/index.html.erb
  Rendered /home/ubuntu/.rvm/gems/ruby-2.6.3/gems/railties-6.0.3/lib/rails/templates/rails/welcome/index.html.erb (Duration: 7.9ms | Allocations: 192)
Completed 200 OK in 12ms (Views: 10.8ms | ActiveRecord: 0.0ms | Allocations: 1165)