get_post_meta returns bool(false)

I’ve been testing and trying to find where it possibly going wrong but i’m stuck on that part. The get_post_meta() is not returning any of my values, tested with a var_dump(get_post_meta(1)) this seems to return it, but when accessing that key var_dump(get_post_meta(1, ‘key_name’)) it’s returning a bool(false).

Also the following way is not working for me, var_dump(get_post_meta(1, ‘key_name’, true)); as by default it’s false so checked this also. In my database the key 100% exists and has got values, also the ID is correct sending this.

<?php 
    var_dump(get_post_meta(1));                // array(4)
    var_dump(get_post_meta(1,'key_name');      // array(1){[0]=>bool(false)}
    var_dump(get_post_meta(1,'key_name',true); // bool(false)
?>

Is there something wrong with WordPress on this or am I missing something here, i’ve got a huge storage of data, could this be a problem for WordPress? Using the latest WordPress version available by download of ww.wp.xz.cn.