Camera Focus is not working

Unity ver: 2017.3.0p4

Vuforia: 7.0.47

Xcode: 9.2

Hi,

I have been trying to make my Vuforia app camera to constantly focus. So i wrote a script and attached it to the ARCamera object. Here's the code: 

using System.Collections; using System.Collections.Generic; using UnityEngine; using Vuforia;

public class CameraFocusController : MonoBehaviour {

// Use this for initialization void Start () {   VuforiaARController.Instance.RegisterVuforiaStartedCallback(OnVuforiaStarted);   VuforiaARController.Instance.RegisterOnPauseCallback(OnPaused);

}

private void OnVuforiaStarted() {   bool focusSet = CameraDevice.Instance.SetFocusMode(    CameraDevice.FocusMode.FOCUS_MODE_CONTINUOUSAUTO);   Debug.Log ("Camera Focus is set: " + focusSet); }

private void OnPaused(bool paused) {   if (!paused) // resumed   {    // Set again autofocus mode when app is resumed    CameraDevice.Instance.SetFocusMode(     CameraDevice.FocusMode.FOCUS_MODE_CONTINUOUSAUTO);   } } }

On the console, focus camera mode is set since focusSet returns TRUE. But the camera focus doesn't work on my iPhone SE. So here are the Xcode's console log when the app is running:

ERROR/AR(53553) 2018-02-22 12:29:46: CameraDevice::getCameraCalibration(): Failed to get camera calibration because the camera is not initialized. cameraDeviceStartCamera Vuforia.CameraDevice:SetFocusMode(FocusMode) CameraFocusController:OnVuforiaStarted() CameraFocusController:Start() Camera Focus is set: True CameraFocusController:OnVuforiaStarted() CameraFocusController:Start()

I tried other mode too but nothing seems to work and I'm lost on the reason why it's not working. 

Thanks,

An