Python / Django / Selenium: "Webdriver Exception: Unable to startphantomjs with ghostdriver"

You might be using an outdated version of Selenium or possibly running it on Windows. Try the latest version of Selenium for Python first.

However, if that doesn't solve your issues you might have a failing test and not closing the webdriver down in your teardown method in your test if you have a custom test case:

CustomLiveServerTestCase(LiveServerTestCase):
    def setUp(self):
        self.wd = webdriver.PhantomJS()
        super(CustomLiveServerTestCase, self).setUp()

    def tearDown(self):
        super(CustomLiveServerTestCase, self).tearDown()
        self.wd.close()