No connection could be made because the target machine actively refused it(selenium)

Question

I have extracted the following code from selenium IDE.(c# remote control)

using System;
using System.Text;
using System.Text.RegularExpressions;
using System.Thr         


        

Answer 1

I get the same error, but on a different line of code. Hopefully this might help someone somewhere even if it doesn't answer the initial question.

    public override void SetupTest()
    {
        Driver = new FirefoxDriver();
        base.SetupTest();
    }

I'm using the WebDriver (I don't run the Selenium server), and the constructor of FirefoxDriver throws the Exception.

Sometimes I get this exception:

A first chance exception of type 'System.Net.Sockets.SocketException' occurred in System.dll
Additional information: No connection could be made because the target machine actively refused it

with this call stack:

    WebDriver.dll!OpenQA.Selenium.Firefox.Internal.ExtensionConnection.ConnectToBrowser(System.TimeSpan timeToWait) Line 247    C#
    WebDriver.dll!OpenQA.Selenium.Firefox.Internal.ExtensionConnection.Start() Line 98  C#
    WebDriver.dll!OpenQA.Selenium.Firefox.FirefoxDriver.StartClient() Line 237  C#
    WebDriver.dll!OpenQA.Selenium.Remote.RemoteWebDriver.RemoteWebDriver(OpenQA.Selenium.Remote.ICommandExecutor commandExecutor, OpenQA.Selenium.ICapabilities desiredCapabilities) Line 89    C#
    WebDriver.dll!OpenQA.Selenium.Firefox.FirefoxDriver.FirefoxDriver(OpenQA.Selenium.Firefox.FirefoxBinary binary, OpenQA.Selenium.Firefox.FirefoxProfile profile, OpenQA.Selenium.ICapabilities capabilities, System.TimeSpan commandTimeout) Line 172    C#
    WebDriver.dll!OpenQA.Selenium.Firefox.FirefoxDriver.FirefoxDriver(OpenQA.Selenium.Firefox.FirefoxBinary binary, OpenQA.Selenium.Firefox.FirefoxProfile profile, System.TimeSpan commandTimeout) Line 167    C#
    WebDriver.dll!OpenQA.Selenium.Firefox.FirefoxDriver.FirefoxDriver(OpenQA.Selenium.Firefox.FirefoxBinary binary, OpenQA.Selenium.Firefox.FirefoxProfile profile) Line 154    C#
    WebDriver.dll!OpenQA.Selenium.Firefox.FirefoxDriver.FirefoxDriver(OpenQA.Selenium.Firefox.FirefoxProfile profile) Line 132  C#
    SetupTest() Line 513    C#

Sometimes I get this exception:

A first chance exception of type 'System.Net.Sockets.SocketException' occurred in System.dll
Additional information: Only one usage of each socket address (protocol/network address/port) is normally permitted

with this call stack:

    WebDriver.dll!OpenQA.Selenium.Firefox.Internal.ExtensionConnection.DetermineNextFreePort(string host, int port) Line 161    C#
    WebDriver.dll!OpenQA.Selenium.Firefox.Internal.ExtensionConnection.Start() Line 88  C#
    [same as above]

But one thing I didn't realize at first is that if you continue execution (F5), everything is fine. The Exception must be handled in the WebDriver.

The only thing is that I had the DEBUG/Exceptions/CLR Exceptions: Thrown [checked]. Just uncheck that and everything runs without throwing/breaking. Took me a while to realize that. Leftovers of a previous debugging session...