Problems with scheduled notifications

Question

I am developing an application that must issue a notification with date and time informed by the user and the notification is not being issued.

I’m using Alarmmanager to set the time and another class I inherit from Broadcastreceiver to launch the notification.

I’ve already declared the Receiver on Androidmanifest.

Class scheduler_vaccine.java

                Intent intent = new Intent(getBaseContext(), AlarmeNotificiation.class);

                PendingIntent pendingIntent = PendingIntent.getBroadcast(getBaseContext(), 0, intent, 0);

                Toast.makeText(agendar_vacina.this, "Dia: "+dia+" Mes: "+mes+" Ano: "+ano, Toast.LENGTH_SHORT).show();

                Calendar c1 = Calendar.getInstance();

                Calendar c = (Calendar) c1.clone();

                c.setTimeInMillis(System.currentTimeMillis());

                //c.set(Calendar.MONTH, mes);
                //c.set(Calendar.YEAR, ano);
                //c.set(Calendar.DAY_OF_MONTH, dia);
                //c.set(Calendar.HOUR_OF_DAY, 11);
                //c.set(Calendar.MINUTE, 33);

                c.set(ano, mes, dia, 12, 02);



                AlarmManager alarmManager = (AlarmManager) getSystemService((getBaseContext().ALARM_SERVICE));

                //alarmManager.set(AlarmManager.RTC_WAKEUP, c.getTimeInMillis(),pendingIntent);

                alarmManager.setExact(AlarmManager.RTC_WAKEUP, c.getTimeInMillis(),pendingIntent);

Alarmenotification class.java

public class AlarmeNotificiation extends BroadcastReceiver {

private static final String CHANNEL_ID = "CHANNEL_ID";
private static final String TAG = "main";


@Override
public void onReceive(Context context, Intent intent) {


    int id = (int) (Math.random()*1000);
    createNotificationChannel(context);

    Intent it = new Intent(context.getApplicationContext(), MainActivity_tela_principal.class);

    PendingIntent pendingIntent = PendingIntent.getBroadcast(context.getApplicationContext(), id,  it, 0);

    NotificationCompat.Builder builder = new NotificationCompat.Builder(context.getApplicationContext(), CHANNEL_ID)
            .setSmallIcon(R.drawable.icon)
            .setContentTitle("Notificação")
            .setContentText("Descrição")
            .setPriority(NotificationCompat.PRIORITY_DEFAULT)
            //.addAction(R.drawable.icon, "Ok", pendingIntent);
            ;


    NotificationManagerCompat notificationManagerCompat = NotificationManagerCompat.from(context.getApplicationContext());

    notificationManagerCompat.notify(id, builder.build());




}



private void createNotificationChannel(Context context) {

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
        CharSequence name =  "Channel name";
        String description = "Channel description";
        int importance = NotificationManager.IMPORTANCE_DEFAULT;
        NotificationChannel channel = new NotificationChannel(CHANNEL_ID, name, importance);
        channel.setDescription(description);
        NotificationManager notificationManager = context.getSystemService(NotificationManager.class);
        notificationManager.createNotificationChannel(channel);
    }
}

}