Notification doesn't show when alarm is triggered

Hi I am implementing a alarm system in my app. I have an alarm manager that triggers a notification everyday in a certain time. It doesn't work as it intended the notification is not displayed at all. Please can anyone help me with these thank you.

my Alarm set code:

val calender = Calendar.getInstance()
calender[Calendar.HOUR_OF_DAY] = hour
calender[Calendar.MINUTE] = minute
calender[Calendar.SECOND] = 0
calender[Calendar.MILLISECOND] = 0

val pendingIntent = PendingIntent.getBroadcast(
    requireContext(),
    0,
    intent,
    PendingIntent.FLAG_IMMUTABLE or PendingIntent.FLAG_UPDATE_CURRENT
)

alarmManager.setInexactRepeating (
    AlarmManager.RTC_WAKEUP,
    calender.timeInMillis,
    AlarmManager.INTERVAL_DAY,
    pendingIntent
)

Broadcast receiver:

class AlarmReceiver : BroadcastReceiver() {
    @RequiresApi(Build.VERSION_CODES.O)
    override fun onReceive(context: Context?, p1: Intent?) {
        val notificationManager =
            context?.getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager

        val notificationCompatBuilder =
            NotificationCompat.Builder(context, Constants.NOTIFICATION_CHANNEL_ID)

        notificationCompatBuilder
            .setContentTitle("Prescript")
            .setContentText("Medicine time.")
            .setSmallIcon(R.mipmap.ic_launcher).priority = NotificationCompat.PRIORITY_DEFAULT

        notificationManager.notify(666, notificationCompatBuilder.build())

        Log.d("TAG", "onReceive: $notificationCompatBuilder")
//        Toast.makeText(context, "Alarm....", Toast.LENGTH_LONG).show();
    }
}