Mobile test using NightwatchJS - ios-simulator

Question

i'm using nightwatchjs with appium for mobile test.
Here is nightwatch.json:
{
"src_folders" : ["./examples/tests"],
"output_folder" : "./examples/reports",
"custom_commands_path" : "./examples/custom-commands",
"page_objects_path" : "./examples/pages",
"custom_assertions_path" : "",
"globals_path" : "",
"live_output" : false,
"parallel_process_delay" : 10,
"disable_colors": false,
"test_workers" : false,
"selenium" : {
"start_process" : false,
"server_path" : "bin/selenium-server-standalone-2.53.1.jar",
"log_path" : "",
"host" : "127.0.0.1",
"port" : 4723,
"cli_args" : {
"webdriver.chrome.driver" : "",
"webdriver.ie.driver" : "",
"webdriver.firefox.profile" : ""
}
},
"test_settings" : {
"default" : {
"launch_url" : "http://localhost",
"selenium_host" : "127.0.0.1",
"selenium_port" : 4723,
"silent" : true,
"disable_colors": false,
"screenshots" : {
"enabled" : false,
"path" : ""
},
"desiredCapabilities" : {
"browserName" : "firefox",
"javascriptEnabled" : true,
"acceptSslCerts" : true
}
},
"ios" : {
"selenium_port" : 4723,
"selenium_host" : "127.0.0.1",
"silent": true,
"desiredCapabilities" : {
"fullReset": false,
"browserName" : "Safari",
"platformName" : "iOS",
"platformVersion" : "9.3",
"deviceName" : "iPhone 6"
}
},
"saucelabs" : {
"selenium_host" : "ondemand.saucelabs.com",
"selenium_port" : 80,
"username" : "${SAUCE_USERNAME}",
"access_key" : "${SAUCE_ACCESS_KEY}",
"use_ssl" : false,
"silent" : true,
"output" : true,
"screenshots" : {
"enabled" : false,
"on_failure" : true,
"path" : ""
},
"desiredCapabilities": {
"name" : "test-example",
"browserName": "firefox"
},
"globals" : {
"myGlobal" : "some_sauce_global"
},
"selenium" : {
"start_process" : false
}
},
"phantomjs" : {
"desiredCapabilities" : {
"browserName" : "phantomjs",
"javascriptEnabled" : true,
"acceptSslCerts" : true,
"phantomjs.binary.path" : "/path/to/phantomjs"
}
},
"browserstack" : {
"selenium" : {
"start_process" : false
},
"selenium_host" : "hub.browserstack.com",
"selenium_port" : 80,
"silent" : true,
"desiredCapabilities": {
"name" : "test-example",
"browserName": "firefox",
"browserstack.user" : "...",
"browserstack.key" : "..."
}
},
"testingbot" : {
"selenium_host" : "hub.testingbot.com",
"selenium_port" : 80,
"apiKey" : "${TB_KEY}",
"apiSecret" : "${TB_SECRET}",
"silent" : true,
"output" : true,
"screenshots" : {
"enabled" : false,
"on_failure" : true,
"path" : ""
},
"desiredCapabilities": {
"name" : "test-example",
"browserName": "firefox"
},
"selenium" : {
"start_process" : false
}
}
}
}
Then,
i start appium and write
bin/nightwatch --env ios -t examples/tests/googlePageObject.js
if it needs to be redirected to google.com,Xcode iphone simulator runs but only redirect 127.0.0.1/4723 and command prompt returns the error that
Error retrieving a new session from the selenium server
Connection refused! Is selenium server started?
{ Error: socket hang up
at createHangUpError (_http_client.js:253:15)
at Socket.socketCloseListener (_http_client.js:285:23)
at emitOne (events.js:101:20)
at Socket.emit (events.js:188:7)
at TCP._handle.close [as _onclose] (net.js:501:12) code: 'ECONNRESET' }
Any Help?