[PHP]: outbrain.com icon headers getting doesn't work using curl, but get_headers works

I'm trying to get http://outbrain.com site icon (http://outbrain.com/favicon.ico) using php 5.6.9 curl with this curl_setopt_array data:

CURLOPT_HTTPHEADER => $request_headers,
CURLOPT_ENCODING => '',
CURLOPT_USERAGENT => '<here_base_page_user_agent>',
CURLOPT_REFERER => 'http://outbrain.com',
CURLOPT_FOLLOWLOCATION => TRUE,
CURLOPT_HEADER => TRUE,
CURLOPT_HTTPGET => TRUE,
CURLOPT_NOBODY => TRUE,
CURLOPT_RETURNTRANSFER => TRUE,
CURLOPT_TIMEOUT => 15,
CURLOPT_SSL_VERIFYPEER => FALSE,
CURLOPT_COOKIEFILE => '/tmp/outbrain.cookie',
CURLOPT_ENCODING => ''

But it returns 403 error.

If I use get_headers function with referrer and user_agent parameters set in stream context - it works.

Help me, please, to find this problem reasons and solution.

What curl options can help?

Thank you in advance!

Solution

Use this URLs instead: