Selenium is giving " KeyError: 'sessionId' "

I am trying to start firefox using selenium but I am constantly getting ``` File "/Library/Python/2.7/site-packages/selenium/webdriver/firefox/webdriver.py", line 150, in __init__ keep_alive=True) File "/Library/Python/2.7/site-packages/selenium/webdriver/remote/webdriver.py", line 92, in __init__ self.start_session(desired_capabilities, browser_profile) File "/Library/Python/2.7/site-packages/selenium/webdriver/remote/webdriver.py", line 180, in start_session self.session_id = response['sessionId'] KeyError: 'sessionId' ``` The code I am trying to run is fairly simple ``` from selenium import webdriver driver = webdriver.Firefox() ``` Solutions I have tried: - Tried updating selenium(I was already using the latest one) - Updated the geckodriver to version 0.16.1 - Tried changing the proxy settings Nothing has worked till now. Configuration I am using: geckodriver 0.16.1 , Mozilla Firefox 53 , Python 2.7 , Selenium 3.4.1 , I am on a Mac system(if that helps)