Starting iOS test (developed in Webdriverio) taking around 6 minutes in real device

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I developed test scenarios in Javascript, using Webdriverio for iOS.
Testing the app in real device. To initiate the test(While passing the capabilities) takes around 6 minutes. After the test started, it ran smoothly.

For My Android test in real device working just fine.
I tried few different version of Appium server
Is there anyone can tell me the possible reason behind this.

Here is the Log, where it takes time to start the tests:

[14:46:28] COMMAND POST “/wd/hub/session”
[14:46:28] DATA {“desiredCapabilities”:{“javascriptEnabled”:true,“locationContextEnabled”:true,“handlesAlerts”:true,“rotatable”:true,“udid”:“XXXXXXXXXXXXX”,“bundleId”:“XXXXXXXXXX”,“platformName”:“iOS”,“platformVersion”:“11.4.1”,“deviceName”:“iPhoneRHM”,“automationName”:“XCUITest”,"_":“3 more keys: [“newCommandTimeout”,“useJSONSource”,“requestOrigins”]”}}

[14:52:06] INFO SET SESSION ID 87d38b90-9a6c-4485-aa61-3c7d5b1eafe3
[14:52:06] RESULT {“webStorageEnabled”:false,“locationContextEnabled”:true,“browserName”:"",“platform”:“MAC”,“javascriptEnabled”:true,“databaseEnabled”:false,“takesScreenshot”:true,“networkConnectionEnabled”:false,“handlesAlerts”:true,“rotatable”:true,“udid”:“XXXXXXXXXX”,“bundleId”:“XXXXXXXX”,“platformName”:“iOS”,“platformVersion”:“11.4.1”,“deviceName”:“iPhoneRHM”,“automationName”:“XCUITest”,“newCommandTimeout”:600000,“useJSONSource”:true,“requestOrigins”:{“url”:“http://webdriver.io”,“version”:“4.13.1”,“name”:“webdriverio”}}

Thanks in Advance

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