drupal sites not opening in poltergeist driver


I am trying to include end to end tests for drupal in my project. 

When I try to run the tests in firefox, the tests run without any issue. But when i try to run the same in Poltergeist / capybara, i am getting DNS server error. 

Can’t open the page itself.

Can anyone help me in this?



Source: https://www.drupal.org/taxonomy/term/2/feed