Cannot Start The Driver Service On Http Localhost Selenium Firefox C -

import io.github.bonigarcia.wdm.WebDriverManager; WebDriverManager.firefoxdriver().setup(); // Auto-downloads and sets path WebDriver driver = new FirefoxDriver();

If you are reading this, you have likely been staring at a red, intimidating stack trace in your console. The error message, often truncated as cannot start the driver service on http://localhost when using Selenium with Firefox, is a classic automation roadblock. import io

from selenium.webdriver.firefox.service import Service service = Service(executable_path='path/to/geckodriver', port=7055) # Classic Selenium port driver = webdriver.Firefox(service=service) If it fails, the entire service crashes with

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. If it fails