java.lang.RuntimeException: Unable to resume activity {com.entitcs.office_attendance/com.entitcs.office_attendance.camera.FaceTrackerActivity}: java.lang.RuntimeException: Fail to connect to camera service
	at android.app.ActivityThread.performResumeActivity(ActivityThread.java:3854)
	at android.app.ActivityThread.handleResumeActivity(ActivityThread.java:3888)
	at android.app.servertransaction.ResumeActivityItem.execute(ResumeActivityItem.java:51)
	at android.app.servertransaction.TransactionExecutor.executeLifecycleState(TransactionExecutor.java:145)
	at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:70)
	at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1843)
	at android.os.Handler.dispatchMessage(Handler.java:106)
	at android.os.Looper.loop(Looper.java:193)
	at android.app.ActivityThread.main(ActivityThread.java:6758)
	at java.lang.reflect.Method.invoke(Native Method)
	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:497)
	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:912)
Caused by: java.lang.RuntimeException: Fail to connect to camera service
	at android.hardware.Camera.<init>(Camera.java:604)
	at android.hardware.Camera.open(Camera.java:424)
	at com.google.android.gms.vision.a.j(Unknown Source:32)
	at com.google.android.gms.vision.a.d(Unknown Source:9)
	at com.entitcs.office_attendance.camera.CameraSourcePreview.f(Unknown Source:29)
	at com.entitcs.office_attendance.camera.CameraSourcePreview.d(Unknown Source:12)
	at com.entitcs.office_attendance.camera.CameraSourcePreview.e(Unknown Source:2)
	at com.entitcs.office_attendance.camera.FaceTrackerActivity.R(Unknown Source:37)
	at com.entitcs.office_attendance.camera.FaceTrackerActivity.onResume(Unknown Source:109)
	at android.app.Instrumentation.callActivityOnResume(Instrumentation.java:1412)
	at android.app.Activity.performResume(Activity.java:7292)
	at android.app.ActivityThread.performResumeActivity(ActivityThread.java:3846)
	... 11 more