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.
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. If you are reading this, you have likely
For Java:
The error occurs only in CI/CD (Jenkins, GitLab CI) but works on your local desktop. Selenium’s default timeout of 20 seconds expires, and
from selenium.webdriver.firefox.service import Service service = Service(executable_path='geckodriver.exe', service_args=['--log', 'debug']) service.start() # Manual start with longer timeout On Windows, SmartScreen or Windows Defender may quarantine
import io.github.bonigarcia.wdm.WebDriverManager; WebDriverManager.firefoxdriver().setup(); // Auto-downloads and sets path WebDriver driver = new FirefoxDriver();
Using port=7055 often resolves conflicts because it's a reserved port for WebDriver. On Windows, SmartScreen or Windows Defender may quarantine or silently block geckodriver.exe because it opens a network port (behavior associated with malware).
