from selenium.webdriver.firefox.options import Options options = Options() options.binary_location = r'C:\Program Files\Mozilla Firefox\firefox.exe' # Windows driver = webdriver.Firefox(options=options) Cause 5: The Headless/Background Mode Trap When running Selenium on a headless server (Linux without a GUI, or Docker container), GeckoDriver attempts to create a graphical display. If it fails, the entire service crashes with the localhost error.
For Java:
from selenium.webdriver.firefox.service import Service service = Service(executable_path='path/to/geckodriver', port=7055) # Classic Selenium port driver = webdriver.Firefox(service=service) from selenium
from selenium.webdriver.firefox.service import Service service = Service( executable_path='geckodriver.exe', service_args=['--log', 'debug'] # Forces verbose output ) driver = webdriver.Firefox(service=service)
This error is Selenium’s way of saying: “I tried to launch Firefox, but the bridge (GeckoDriver) connecting me to the browser collapsed before the connection could be established.” Selenium’s default timeout of 20 seconds expires, and
import io.github.bonigarcia.wdm.WebDriverManager; WebDriverManager.firefoxdriver().setup(); // Auto-downloads and sets path WebDriver driver = new FirefoxDriver();
from pyvirtualdisplay import Display display = Display(visible=0, size=(1920, 1080)) display.start() # Your Firefox driver code here Sometimes, GeckoDriver starts the HTTP server slowly (slow disk, high CPU). Selenium’s default timeout of 20 seconds expires, and it kills the process. or Docker container)
from selenium.webdriver.firefox.service import Service service = Service(executable_path='geckodriver.exe', service_args=['--log', 'debug']) service.start() # Manual start with longer timeout