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

// Ensure geckodriver.exe is in the same folder as your .exe or in PATH var options = new FirefoxOptions(); options.AddArgument("--headless"); // optional: headless mode

var driver = new FirefoxDriver(options); // will search PATH driver.Navigate().GoToUrl("https://example.com"); Console.WriteLine(driver.Title); driver.Quit(); // Ensure geckodriver

Below, I break down exactly why this happens and the 7 most effective fixes. OpenQA.Selenium.WebDriverException: Cannot start the driver service on http://localhost:xxxx/ ---> System.Net.Sockets.SocketException: Only one usage of each socket address (protocol/network address/port) is normally permitted. Root Cause Analysis The error indicates a port conflict or driver process failure . The geckodriver tries to bind to a port on localhost , but something is blocking it. The geckodriver tries to bind to a port

var service = FirefoxDriverService.CreateDefaultService(@"C:\path\to\geckodriver"); service.Port = 12345; // Use any free port above 1024 var driver = new FirefoxDriver(service); | Firefox Version | GeckoDriver Version | |----------------|---------------------| | 115+ (ESR) | 0.33+ | | 120+ | 0.34+ | | 130+ | 0.35+ | service.Port = 12345

taskkill /F /IM geckodriver.exe