Cannot Access ViewModel in DialogFragment - android-studio

Question

I'm trying to retrive dates from database using using month and year in Dialog Fragment. But the problem is it is showing error while executing.
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.untolddiary, PID: 21823
java.lang.IllegalStateException: Can't access ViewModels from detached fragment
at androidx.fragment.app.Fragment.getViewModelStore(Fragment.java:414)
at androidx.lifecycle.ViewModelProvider.<init>(ViewModelProvider.kt:118)
at com.example.untolddiary.CalenderFragment.<init>(CalenderFragment.kt:46)
at com.example.untolddiary.MainActivity.onCreate$lambda$2(MainActivity.kt:111)
at com.example.untolddiary.MainActivity.$r8$lambda$JiX3NTZFHpQbKFS4nkkCvOkq6Q8(Unknown Source:0)
at com.example.untolddiary.MainActivity$$ExternalSyntheticLambda4.onClick(Unknown Source:2)
at android.view.View.performClick(View.java:7766)
at android.view.View.performClickInternal(View.java:7739)
at android.view.View.access$3700(View.java:860)
at android.view.View$PerformClick.run(View.java:29330)
at android.os.Handler.handleCallback(Handler.java:938)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loopOnce(Looper.java:210)
at android.os.Looper.loop(Looper.java:299)
at android.app.ActivityThread.main(ActivityThread.java:8306)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:576)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1073)
Dialog Fragment
class CalenderFragment : DialogFragment() {
private val viewModel = ViewModelProvider(this).get(DViewModel::class.java)
private fun setMonthView() {
var calenderHighlighter = CalenderHighlighter()
calenderHighlighter.positionsList(viewModel.retrivePositions(MonthSeperator(selectedDate!!)!!.toInt()
, YearSeperator(selectedDate!!)!!.toInt()))
}
}