Selenium/Linux throws exception "An unknown exception was encountered sending an HTTP request to the remote WebDriver server for URL "

Question

I am trying to port some Selenium-Tests that I developed under windows (my main platform) to Linux (Ubuntu 19.10 in a VM). I must admit, I'm not too familiar with the environment, so I might be missing very obvious things - well, obvious for those that live on Linux ;)

After fixing issues with file permissions for the driver etc., I am stopped with this exception:

OpenQA.Selenium.WebDriverException: An unknown exception was encountered sending an HTTP request to the remote WebDriver server for URL http://localhost:39213/session. The exception message was: Connection refused
 ---> System.Net.Http.HttpRequestException: Connection refused
 ---> System.Net.Sockets.SocketException (111): Connection refused
 at System.Net.Http.ConnectHelper.ConnectAsync(String host, Int32 port, CancellationToken cancellationToken)
 --- End of inner exception stack trace ---
 at System.Net.Http.ConnectHelper.ConnectAsync(String host, Int32 port, CancellationToken cancellationToken)
 at System.Net.Http.HttpConnectionPool.ConnectAsync(HttpRequestMessage request, Boolean allowHttp2, CancellationToken cancellationToken)
 at System.Net.Http.HttpConnectionPool.CreateHttp11ConnectionAsync(HttpRequestMessage request, CancellationToken cancellationToken)
 at System.Net.Http.HttpConnectionPool.GetHttpConnectionAsync(HttpRequestMessage request, CancellationToken cancellationToken)
 at System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage request, Boolean doRequestAuth, CancellationToken cancellationToken)
 at System.Net.Http.RedirectHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
 at System.Net.Http.HttpClient.FinishSendAsyncBuffered(Task`1 sendTask, HttpRequestMessage request, CancellationTokenSource cts, Boolean disposeCts)
 at OpenQA.Selenium.Remote.HttpCommandExecutor.MakeHttpRequest(HttpRequestInfo requestInfo)
 at OpenQA.Selenium.Remote.HttpCommandExecutor.Execute(Command commandToExecute)
 --- End of inner exception stack trace ---
 at OpenQA.Selenium.Remote.HttpCommandExecutor.Execute(Command commandToExecute)
 at OpenQA.Selenium.Remote.DriverServiceCommandExecutor.Execute(Command commandToExecute)
 at OpenQA.Selenium.Remote.RemoteWebDriver.Execute(String driverCommandToExecute, Dictionary`2 parameters)
 at OpenQA.Selenium.Remote.RemoteWebDriver.StartSession(ICapabilities desiredCapabilities)
 at OpenQA.Selenium.Remote.RemoteWebDriver..ctor(ICommandExecutor commandExecutor, ICapabilities desiredCapabilities)
 at OpenQA.Selenium.Chromium.ChromiumDriver..ctor(ChromiumDriverService service, ChromiumOptions options, TimeSpan commandTimeout)
 at OpenQA.Selenium.Chrome.ChromeDriver..ctor(ChromeDriverService service, ChromeOptions options, TimeSpan commandTimeout)
 at OpenQA.Selenium.Chrome.ChromeDriver..ctor(ChromeDriverService service, ChromeOptions options)

when trying to instantiate ChromeDriver (by passing an instance of ChromeDriverService and some ChromeOptions.

How can I diagnose/fix this?

The webserver I would like to talk to listens on 10.0.2.15:8080 and delivers content to a regular browser. A coworker recommended to try netstat -an | grep 39213 to see if anything is actually listing on that port - which was not the case (no output from that command). And indeed - the service did not launch. I have an instance of ChromeDriverService - but there is no process associated with it. Will look into that now and update the question if I find anything useful...

• pavelsaman: What's the actual IP addr of localhost? And of your WebDriver server? Are they the same? Isn't onesth like 127.1.0.0 and the other one 127.0.0.1?
• Mohamed Sulaimaan Sheriff: In which machine your WebDriver server is running? Whether in local machine or else in some other remote machine
• Alexey R.: What is your linux distro?
• PDHide: Have you started selenium server before running your script ?
• MBaas: Answered 1 (partially) and 2+3 by adding to the question. Not sure what you guys mean with "Selenium Server". The "pattern" I learned on windows is to first create a ChromeDriverService and then pass that instance to the ChromeDriver. And it's all happening on this machine - no external calls needed.

Answer 1

Argh - found it: the file chromedriver. did not have execute-permissions. That wasn't reported as a problem when I instantiated ChromeDriverService - but I also did not create a "regular instance" of it. After setting these permissions, it's running now!

• Sasan: Could you pleas take a look at stackoverflow.com/questions/73020234/… . I have this problem with Docker
• MBaas: I had a look - but my feeling is that the issue there is something else, probably more with Docker - which I'm still learning about...