What can cause `UnreachableBrowserException: Could not start a new session`?

Question

I try to run a selenium client that interacts with remote selenium web driver server.

Some (only some) of my tests are failing because of connection refused.

What should I check on the machine that hosts the server?

com.x.inject.ProvisionException: Guice provision errors:

    1) Error in custom provider, org.openqa.selenium.remote.UnreachableBrowserException: Could not start a new session. Possible causes are invalid address of the remote server or browser start-up failure.
    Build info: version: '2.44.0', revision: '76d78cf323ce037c5f92db6c1bba601c2ac43ad8', time: '2014-10-23 13:11:40'
    System info: host: 'w04.hfa.corp.x.com', ip: '172.28.144.7', os.name: 'Linux', os.arch: 'amd64', os.version: '3.13.0-30-generic', java.version: '1.8.0_25'
    Driver info: driver.version: RemoteWebDriver
      while locating com.waze.testing.guice.providers.WebDriverProvider
      at com.waze.testing.MainModule.configure(MainModule.java:44)
      while locating org.openqa.selenium.WebDriver

    1 error
        at com.x.inject.internal.InjectorImpl$2.get(InjectorImpl.java:1009)
        at com.x.inject.internal.InjectorImpl.getInstance(InjectorImpl.java:1035)
        at com.waze.testing.cucumber.steps.Hooks.before(Hooks.java:39)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

Answer 1

Selenium 2.44 and "Native Method" phrase in the traceback makes me think this is a compatibility problem. Upgrade selenium to the latest (2.46 currently) version.