Wrong version of vagrant?
Installing the 'vagrant-aws' plugin. This can take a few minutes... /usr/lib/ruby/2.3.0/rubygems/specification.rb:2289:in `raise_if_conflicts': Unable to activate fog-1.42.0, because json-1.8.3 conflicts with json (~> 2.0) (Gem::ConflictError) from /usr/lib/ruby/2.3.0/rubygems/specification.rb:1410:in `activate' from /usr/share/rubygems-integration/all/gems/vagrant-1.9.1/lib/vagrant/bundler.rb:323:in `block in activate_solution' from /usr/share/rubygems-integration/all/gems/vagrant-1.9.1/lib/vagrant/bundler.rb:320:in `each' from /usr/share/rubygems-integration/all/gems/vagrant-1.9.1/lib/vagrant/bundler.rb:320:in `activate_solution' from /usr/share/rubygems-integration/all/gems/vagrant-1.9.1/lib/vagrant/bundler.rb:248:in `internal_install' from /usr/share/rubygems-integration/all/gems/vagrant-1.9.1/lib/vagrant/bundler.rb:98:in `install' from /usr/share/rubygems-integration/all/gems/vagrant-1.9.1/lib/vagrant/plugin/manager.rb:62:in `block in install_plugin' from /usr/share/rubygems-integration/all/gems/vagrant-1.9.1/lib/vagrant/plugin/manager.rb:72:in `install_plugin' from /usr/share/rubygems-integration/all/gems/vagrant-1.9.1/plugins/commands/plugin/action/install_gem.rb:37:in `call' from /usr/share/rubygems-integration/all/gems/vagrant-1.9.1/lib/vagrant/action/warden.rb:34:in `call' from /usr/share/rubygems-integration/all/gems/vagrant-1.9.1/lib/vagrant/action/builder.rb:116:in `call' from /usr/share/rubygems-integration/all/gems/vagrant-1.9.1/lib/vagrant/action/runner.rb:66:in `block in run' from /usr/share/rubygems-integration/all/gems/vagrant-1.9.1/lib/vagrant/util/busy.rb:19:in `busy' from /usr/share/rubygems-integration/all/gems/vagrant-1.9.1/lib/vagrant/action/runner.rb:66:in `run' from /usr/share/rubygems-integration/all/gems/vagrant-1.9.1/plugins/commands/plugin/command/base.rb:14:in `action' from /usr/share/rubygems-integration/all/gems/vagrant-1.9.1/plugins/commands/plugin/command/install.rb:32:in `block in execute' from /usr/share/rubygems-integration/all/gems/vagrant-1.9.1/plugins/commands/plugin/command/install.rb:31:in `each' from /usr/share/rubygems-integration/all/gems/vagrant-1.9.1/plugins/commands/plugin/command/install.rb:31:in `execute' from /usr/share/rubygems-integration/all/gems/vagrant-1.9.1/plugins/commands/plugin/command/root.rb:66:in `execute' from /usr/share/rubygems-integration/all/gems/vagrant-1.9.1/lib/vagrant/cli.rb:42:in `execute' from /usr/share/rubygems-integration/all/gems/vagrant-1.9.1/lib/vagrant/environment.rb:274:in `cli' from /usr/share/rubygems-integration/all/gems/vagrant-1.9.1/bin/vagrant:122:in `<top (required)>' from /usr/bin/vagrant:22:in `load' from /usr/bin/vagrant:22:in `<main>'