title: Xlib: extension "RANDR" missing on display ":99"
body: <p>I have run into an issue. Whenever I run my test class it is showing the following error:  </p>
  
  <pre><code>Testsuite: com.lo.test.selenium.AssignCampaignTestCase
  Tests run: 1, Failures: 0, Errors: 1, Time elapsed: 46.991 sec
  ------------- Standard Error -----------------
  org.openqa.selenium.firefox.NotConnectedException: Unable to connect to host 127.0.0.1 on port 7055 after 45000 ms. Firefox console output:
  Xlib:  extension "RANDR" missing on display ":99".
  *** LOG addons.manager: Application has been upgraded
  *** LOG addons.xpi: startup
  *** LOG addons.xpi: Ignoring file entry whose name is not a valid add-on ID: /tmp/anonymous4942696774897131989webdriver-profile/extensions/webdriver-staging
  *** LOG addons.xpi: checkForChanges
  *** LOG addons.xpi-utils: Opening database
  *** LOG addons.xpi-utils: Creating database schema
  *** LOG addons.xpi: New add-on fxdriver@googlecode.com installed in app-profile
  *** LOG addons.xpi: New add-on {972ce4c6-7e08-4474-a285-3208198ce6fd} installed in app-global
  *** LOG addons.xpi: Updating database with changes to installed add-ons
  *** LOG addons.xpi-utils: Updating add-on states
  *** LOG addons.xpi-utils: Writing add-ons list
  *** LOG addons.manager: shutdown
  *** LOG addons.xpi: shutdown
  *** LOG addons.xpi-utils: shutdown
  *** LOG addons.xpi-utils: Database closed
  Xlib:  extension "RANDR" missing on display ":99".
  *** LOG addons.xpi: startup
  *** LOG addons.xpi: Ignoring file entry whose name is not a valid add-on ID: /tmp/anonymous4942696774897131989webdriver-profile/extensions/webdriver-staging
  *** LOG addons.xpi: checkForChanges
  *** LOG addons.xpi: No changes found
  
          at org.openqa.selenium.firefox.internal.NewProfileExtensionConnection.start(NewProfileExtensionConnection.java:109)
          at org.openqa.selenium.firefox.FirefoxDriver.startClient(FirefoxDriver.java:245)
          at org.openqa.selenium.remote.RemoteWebDriver.&lt;init&gt;(RemoteWebDriver.java:109)
  </code></pre>
  
  <p>My test class:</p>
  
  <pre><code>package com.lo.test.selenium; 
  
  import static org.junit.Assert.assertTrue;
  import static org.junit.Assert.fail;
  
  import java.util.Properties;
  import java.util.ResourceBundle;
  
  import javax.mail.Flags;
  import javax.mail.Folder;
  import javax.mail.Message;
  import javax.mail.MessagingException;
  import javax.mail.NoSuchProviderException;
  import javax.mail.Session;
  import javax.mail.Store; 
  import org.junit.Test;
  import org.openqa.selenium.By;
  import org.openqa.selenium.WebDriver;
  import org.openqa.selenium.WebElement;
  import org.openqa.selenium.firefox.FirefoxDriver;
  import org.openqa.selenium.support.ui.ExpectedConditions;
  import org.openqa.selenium.support.ui.Select;
  import org.openqa.selenium.support.ui.WebDriverWait;
  
  public class MyExampleTestCase {
  
      private static ResourceBundle rb = ResourceBundle.getBundle("global-messages");
  
      static WebDriver driver = new FirefoxDriver();  //Make it static in order to make one instance of this class(helps to avoid opening of 2 browsers at once)
  
      @Test
      public void campaignEmailTestCase() throws InterruptedException { 
          MyExampleTestCase emTesObj = new MyExampleTestCase ();  
          String fName = "test LO";
          Integer LeadId = 570903;
          String campaignName = "2Get"; 
          String SubjName = "Welcome"; //NOTE: No problem, Type without double quotes. It will work for you 
  
          emTesObj.doLogin(); 
          emTesObj.goToLeadsListPage();
          emTesObj.searchByFirstName(fName); //without this also,it will work but gives you the correct navigation on UI
          emTesObj.waitBeforePageLoads(LeadId.toString()); //pass the Id attribute which you aspect to see after the page is loaded
          emTesObj.assignCampaign(LeadId, campaignName);  
          emTesObj.readRecentEmail(SubjName);  
      }
  }
  </code></pre>
  
  <p><strong>Update:</strong></p>
  
  <p>I tried the code below but it still is showing the same error after executing this code and <a href="https://i.stack.imgur.com/qeS4j.jpg" rel="nofollow noreferrer">also showed some error with this code</a></p>
  
  <pre><code>Xvfb :21 -screen 0 1024x768x24 -extension RANDR &amp;
  </code></pre>
  
  <p>Looks like this code did not run properly. Could someone please help me with this?</p>