title: Cannot launch Safari browser with Nightwatch
body: <p>I am using Nightwatch.js to build/run end to end tests on our web app, and as part of our build process, we want to integrate it with Jenkins.  On my local machine, I am able to run my tests, on all three browsers (Firefox, Safari, Chrome) at the same time with no issue.  I can also run on an individual browser with no issue.  I have the correct and most recent versions of the selenium driver, and am pointing to them in my nightwatch.json file.  For some reason, however, I am not able to launch Safari on the dedicated machine that is running these tests when a new Jenkins build comes in.  Everything is set up the exact same way on that machine as it is on my on, but I keep getting the error</p>
  
  <pre><code>     Error retrieving a new session from the selenium server
       Failed to connect to SafariDriver after 10066ms
  </code></pre>
  
  <p>When this happens, both Chrome and Firefox are able to load with no problem, only Safari has the issue.  We made sure to download the most recent version of the standalone selenium driver for Safari, and I did it again just to be sure.  I've also made sure to check if there happens to be another instance of the selenium server running, but it's never the case</p>
  
  <p>My nightwatch.json file looks like this....</p>
  
  <pre><code>     {
        "src_folders" : ["test"],
        "output_folder" : "reports",
        "custom_commands_path" : "node_modules/nightwatch-custom-commands-         assertions/js/commands",
        "custom_assertions_path" : "node_modules/nightwatch-custom-commands-assertions/js/assertions",
        "page_objects_path" : "",
        "globals_path" : "",
  
        "selenium" : {
          "start_process" : true,
          "server_path" : "lib/selenium-server-standalone-2.53.0.jar",
          "log_path" : "",
          "host" : "127.0.0.1",
          "port" : 4444,
          "cli_args" : {
           "webdriver.chrome.driver" : "lib/chromedriver",
           "webdriver.safari.driver" : "lib/selenium-server-standalone-2.53.0.jar"
           }
        },
  
        "test_settings" : {
          "firefox" : {
             "launch_url" : "http://localhost",
             "selenium_port"  : 4444,
             "selenium_host"  : "localhost",
             "silent": true,
             "screenshots" : {
               "enabled" : false,
               "path" : "./screenshots"
             },
            "desiredCapabilities": {
              "browserName": "firefox",
              "javascriptEnabled": true,
              "acceptSslCerts": true
             },
            "end_session_on_fail": false,
            "skip_testcase_on_fail": false
          },
  
          "chrome" : {
            "launch_url" : "http://localhost",
            "selenium_port"  : 4444,
            "selenium_host"  : "localhost",
            "silent": true,
            "screenshots" : {
              "enabled" : false,
              "path" : "./screenshots"
            },
            "desiredCapabilities": {
              "browserName": "chrome",
              "javascriptEnabled": true,
              "acceptSslCerts": true
            },
            "end_session_on_fail": false,
            "skip_testcase_on_fail": false
          },
  
          "safari" : {
            "launch_url" : "http://localhost",
            "selenium_port"  : 4444,
            "selenium_host"  : "localhost",
            "silent": true,
            "screenshots" : {
              "enabled" : false,
              "path" : "./screenshots"
            },
            "desiredCapabilities" : {
              "browserName" : "safari",
              "javascriptEnabled" : true,
              "acceptSslCerts" : true
            },
            "end_session_on_fail": false,
            "skip_testcase_on_fail": false
         }
      }
   }
  </code></pre>
  
  <p>If anyone has any insight to why this might be happening I'd appreciate it.  Thanks</p>