Rails server keeps exiting (binder.rb:249) error

Question

I'm really new to ruby and rails and I was trying to follow the odin project's installfest but couldn't seem to get past thru the install phase. I tried running rails server but it keeps exiting and giving me this error. Can anyone help? Thank you very much.

=> Booting Puma
=> Rails 5.0.2 application starting in development on http://localhost:3000
=> Run `rails server -h` for more startup options
Puma starting in single mode...
* Version 3.8.2 (ruby 2.3.3-p222), codename: Sassy Salamander
* Min threads: 5, max threads: 5
* Environment: development
* Listening on tcp://localhost:3000
Exiting
/Users/macbookpro/.rvm/gems/ruby-2.3.3/gems/puma-3.8.2/lib/puma/binder.rb:249:in `gethostbyname': getaddrinfo: nodename nor servname provided, or not known (SocketError)
    from /Users/macbookpro/.rvm/gems/ruby-2.3.3/gems/puma-3.8.2/lib/puma/binder.rb:249:in `localhost_addresses'
    from /Users/macbookpro/.rvm/gems/ruby-2.3.3/gems/puma-3.8.2/lib/puma/binder.rb:262:in `add_tcp_listener'
    from /Users/macbookpro/.rvm/gems/ruby-2.3.3/gems/puma-3.8.2/lib/puma/binder.rb:105:in `block in parse'
    from /Users/macbookpro/.rvm/gems/ruby-2.3.3/gems/puma-3.8.2/lib/puma/binder.rb:88:in `each'
    from /Users/macbookpro/.rvm/gems/ruby-2.3.3/gems/puma-3.8.2/lib/puma/binder.rb:88:in `parse'
    from /Users/macbookpro/.rvm/gems/ruby-2.3.3/gems/puma-3.8.2/lib/puma/runner.rb:144:in `load_and_bind'
    from /Users/macbookpro/.rvm/gems/ruby-2.3.3/gems/puma-3.8.2/lib/puma/single.rb:87:in `run'
    from /Users/macbookpro/.rvm/gems/ruby-2.3.3/gems/puma-3.8.2/lib/puma/launcher.rb:172:in `run'
    from /Users/macbookpro/.rvm/gems/ruby-2.3.3/gems/puma-3.8.2/lib/rack/handler/puma.rb:64:in `run'
    from /Users/macbookpro/.rvm/gems/ruby-2.3.3/gems/rack-2.0.1/lib/rack/server.rb:296:in `start'
    from /Users/macbookpro/.rvm/gems/ruby-2.3.3/gems/railties-5.0.2/lib/rails/commands/server.rb:79:in `start'
    from /Users/macbookpro/.rvm/gems/ruby-2.3.3/gems/railties-5.0.2/lib/rails/commands/commands_tasks.rb:90:in `block in server'
    from /Users/macbookpro/.rvm/gems/ruby-2.3.3/gems/railties-5.0.2/lib/rails/commands/commands_tasks.rb:85:in `tap'
    from /Users/macbookpro/.rvm/gems/ruby-2.3.3/gems/railties-5.0.2/lib/rails/commands/commands_tasks.rb:85:in `server'
    from /Users/macbookpro/.rvm/gems/ruby-2.3.3/gems/railties-5.0.2/lib/rails/commands/commands_tasks.rb:49:in `run_command!'
    from /Users/macbookpro/.rvm/gems/ruby-2.3.3/gems/railties-5.0.2/lib/rails/commands.rb:18:in `<top (required)>'
    from /Users/macbookpro/railsbridge/test_app/bin/rails:9:in `require'
    from /Users/macbookpro/railsbridge/test_app/bin/rails:9:in `<top (required)>'
    from /Users/macbookpro/.rvm/gems/ruby-2.3.3/gems/spring-2.0.1/lib/spring/client/rails.rb:28:in `load'
    from /Users/macbookpro/.rvm/gems/ruby-2.3.3/gems/spring-2.0.1/lib/spring/client/rails.rb:28:in `call'
    from /Users/macbookpro/.rvm/gems/ruby-2.3.3/gems/spring-2.0.1/lib/spring/client/command.rb:7:in `call'
    from /Users/macbookpro/.rvm/gems/ruby-2.3.3/gems/spring-2.0.1/lib/spring/client.rb:30:in `run'
    from /Users/macbookpro/.rvm/gems/ruby-2.3.3/gems/spring-2.0.1/bin/spring:49:in `<top (required)>'
    from /Users/macbookpro/.rvm/gems/ruby-2.3.3/gems/spring-2.0.1/lib/spring/binstub.rb:31:in `load'
    from /Users/macbookpro/.rvm/gems/ruby-2.3.3/gems/spring-2.0.1/lib/spring/binstub.rb:31:in `<top (required)>'
    from /Users/macbookpro/railsbridge/test_app/bin/spring:15:in `require'
    from /Users/macbookpro/railsbridge/test_app/bin/spring:15:in `<top (required)>'
    from bin/rails:3:in `load'
    from bin/rails:3:in `<main>'

Answer 1

you can try to delete server.pid that is in tmp/pids path. it is probably you have already started the server in another terminal tab or window.