Harvester Give a Blank Plain Txt File ??

hey Guys,my second post here,everyday i'm got another hacking tutorial,another suggestion,and also got some new way to learn,and yes thanks for you guys and thanks for this good site,im really like it.

i'm got another problem when exploring my linux because im a little bit new with this linux machine.

im trying site cloner with social engineering toolkit and cloning facebook for example.

everything works fine at the beginning,and also im already set up my apache2,index.html,and my post.php

when i'm access the cloned site with my phone,the cloned site load to fake facebook perfectly,and i'm fill the log-in and password,as we know the phising site will redirected us to real facebook site and we have too fill the log-in again,

after that im tryn to check the harvester.txt file but im just got a blank txt file....did i miss something or what ??