Cannot Start The Driver Service On Http Localhost Selenium Firefox C ^hot^ May 2026

OpenQA.Selenium.WebDriverException: Cannot start the driver service on http://localhost:XXXX/

Or let Selenium choose a random free port (default behavior):

Do not specify a port manually unless necessary. Remove port=4444 from your service constructor. OpenQA

Missing or Incorrect Driver Path:

The FirefoxDriver cannot find the geckodriver.exe file in your application's bin folder or the path specified in your code. Temporarily disable Windows Defender Firewall or add an

static void Main()

Alternatively, set the global implicit wait or use WebDriverWait on creation

// Define the service using that path FirefoxDriverService service = FirefoxDriverService.CreateDefaultService(driverPath); OpenQA