Не совсем понимаю в чём ошибка, при переходе на другой экран идёт сбой

Ошибка

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.whac_a_mole, PID: 6818
    java.lang.IllegalStateException: Fragment GameFragment{8974524} (a172df17-d1e2-45b8-9c83-22b1dd2c1e28) not attached to a context.
        at androidx.fragment.app.Fragment.requireContext(Fragment.java:900)
        at androidx.fragment.app.Fragment.getResources(Fragment.java:964)
        at com.example.whac_a_mole.screens.GameFragment$Game$2$1.run(GameFragment.kt:51)
        at android.os.Handler.handleCallback(Handler.java:938)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:223)
        at android.app.ActivityThread.main(ActivityThread.java:7656)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)

Моя активность

class GameFragment : Fragment(R.layout.fragment_game) {
    val timeTxt: Int = 30
    override fun onStart() {
        super.onStart()
        Game()
    }
    fun Game() {
        var holeList = mutableListOf(im1, im2, im3, im4, im5, im6, im7, im8, im9)
        val random = Random
        val score: Int = 0
        view_timer.text = timeTxt.toString()
        fixedRateTimer("timer", false, 600, 700) {
            APP_ACTIVITY.runOnUiThread {
                var redHole = holeList[random.nextInt(holeList.size)]

                redHole.setImageDrawable(resources.getDrawable(R.drawable.ic_mole))
            }
        }
        fixedRateTimer("timer", false, 0, 800) {
            APP_ACTIVITY.runOnUiThread {
                for (i in 0 until holeList.size) {
                    var blackhole = holeList[i]
                    blackhole!!.setImageDrawable(resources.getDrawable(R.drawable.ic_hole1))
                }
            }
        }
        val timer = object : CountDownTimer(30000, 1000) {
            override fun onTick(millisUntilFinished: Long) {
                timeTxt - 1

            }

            override fun onFinish() {
                replaceFragment(ScoreFragment(), false)
            }
        }
        timer.start()
    }
}

`