Firefox is not navigating to the URL and TestWise is showing timeout errror (Rspec, Selenium WebDriver)

Question

I am learning rspec with selenium webdriver using testwise. I created a project and given a url and created a new test case and tried to run it. While running it is opening Firefox automatically.but not navigating to the given url(gmail.com)

Here's my code

load File.dirname(__FILE__) + '/test_helper.rb'

describe "Test Suite" do
  include TestHelper

  before(:all) do    
    @browser = $browser = Selenium::WebDriver.for(browser_type)
    @browser.navigate.to(site_url)
  end

  after(:all) do
    @browser.quit unless debugging?
  end

  it "New Test Case" do
    # Test Steps go here
  end

end