Routes for Subdomain not accessible in Cucumber

I m using rails 3 and writing test cases using cucumber. My Feature file is look like

Feature: Create a New Email Header Footer
As a Competition Admin
I want to update a Email Header Footer

Background:
  Given a pay-to-enter competition

Scenario: Edit email HeaderFooter
  When an open pay-to-enter competition is given
  And I am logged in as a competition admin
  And I am on the Email HeaderFooter Edit Page
  And I update Email Header Footer Content

Step Definition for

When(/^I am on the Email HeaderFooter Edit Page$/) do
  visit url_for_email_notification_header_footer(@current_comp)
  expect(current_path).to match email_notification_header_footers_edit_path
end

where url_for_email_notification_header_footer(@current_comp) is a method which returns url with subdomain.

e.g for abc competition it will return http://ift.tt/1ZHJ0eP

But visit url_for_email_notification_header_footer(@current_comp) is redirecting to the 500.html. Why subdomain routes are not accessible?