Loading Page using iframe (Elgg 2.3.3)

I want to load a local page using iframe on a page but I am getting a prompt "for security reasons framing is not allowed; click ok to remove the frames elgg"

Here's my page code:

$vars['src'] = elgg_normalize_url("mod/online_cv/views/default/online_cv/elements/online_cv.php");
echo elgg_format_element('iframe', $vars);

Here the screenshot: