when using OmniAuth in rails application why I always met Errno::ETIMEDOUT

I have a rails dummy application, And I've add OmniAuth into my Gemfile. I've add

<%= link_to "Sign in with Twitter", "/auth/twitter" %>

in my application layout file.

Also I've add the omniauth.rb file in my config\initializers folder.

Rails.application.config.middleware.use OmniAuth::Builder do
  provider :tw开发者_开发知识库itter, 'MYKEY', 'MYSECERT'
end

After I restart of my rails server with rails s and visit http://localhost:3000/auth/twitter

I've always met Errno::ETIMEDOUT, saying Operation timed out - connect(2)

My computer can visit Twitter website meanwhile.

Can anyone help me what was going wrong here? Thank you very much.

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That is because of the network issue. After connected with VPN, everything was fine.