Unable to start rails server in Rails 5

Question

I installed Rails using RVM. Everything works fine like generating a new app with rails new app . bundle install and every other command runs fine as well. But when I start my Rails server with rails -server I get the following error, which I'm not able to understand.

rails aborted!
NameError: undefined local variable or method `rver' for #<Rake::Application:0x00563aa7540988>
/home/mrrobot/.rvm/gems/ruby-2.4.0@global/gems/railties-5.0.2/lib/rails/commands/rake_proxy.rb:12:in `block in run_rake_task'
/home/mrrobot/.rvm/gems/ruby-2.4.0@global/gems/railties-5.0.2/lib/rails/commands/rake_proxy.rb:11:in `run_rake_task'
/home/mrrobot/.rvm/gems/ruby-2.4.0@global/gems/railties-5.0.2/lib/rails/commands/commands_tasks.rb:51:in `run_command!'
/home/mrrobot/.rvm/gems/ruby-2.4.0@global/gems/railties-5.0.2/lib/rails/commands.rb:18:in `<top (required)>'
/home/mrrobot/rails/demo/app/bin/rails:9:in `require'
/home/mrrobot/rails/demo/app/bin/rails:9:in `<top (required)>'
/home/mrrobot/.rvm/gems/ruby-2.4.0@global/gems/spring-2.0.1/lib/spring/client/rails.rb:28:in `load'
/home/mrrobot/.rvm/gems/ruby-2.4.0@global/gems/spring-2.0.1/lib/spring/client/rails.rb:28:in `call'
/home/mrrobot/.rvm/gems/ruby-2.4.0@global/gems/spring-2.0.1/lib/spring/client/command.rb:7:in `call'
/home/mrrobot/.rvm/gems/ruby-2.4.0@global/gems/spring-2.0.1/lib/spring/client.rb:30:in `run'
/home/mrrobot/.rvm/gems/ruby-2.4.0@global/gems/spring-2.0.1/bin/spring:49:in `<top (required)>'
/home/mrrobot/.rvm/gems/ruby-2.4.0@global/gems/spring-2.0.1/lib/spring/binstub.rb:31:in `load'
/home/mrrobot/.rvm/gems/ruby-2.4.0@global/gems/spring-2.0.1/lib/spring/binstub.rb:31:in `<top (required)>'
/home/mrrobot/rails/demo/app/bin/spring:15:in `require'
/home/mrrobot/rails/demo/app/bin/spring:15:in `<top (required)>'
bin/rails:3:in `load'
bin/rails:3:in `<main>'
(See full trace by running task with --trace)

Ruby version: 2.4.0p0 (2016-12-24 revision 57164) [x86_64-linux]

Rails version: 5.0.2

RubyGems version: 2.6.11

Answer 1

It's rails server , without dash

or just

rails s