curl post php 403 forbidden -

i'm tring post data using post methode , curl excute , result

403 - forbidden: access denied.
not have permission view directory or page using credentials supplied.

$request=''; $url='https://app.highwire.com/api/auth'; $header=array('mydata'); $con = curl_init();      curl_setopt($con, curlopt_url, $url);     curl_setopt($con, curlopt_ssl_verifypeer, 0);     curl_setopt($con, curlopt_ssl_verifyhost, 0);     curl_setopt($con, curlopt_header, true);     curl_setopt($con, curlopt_httpheader, $header);     curl_setopt($con, curlopt_post, 1);     curl_setopt($con, curlopt_postfields, $request);     curl_setopt($con, curlopt_returntransfer, true);     curl_setopt($con, curlopt_failonerror, 0);     curl_setopt($con, curlopt_useragent, 'mozilla/5.0 (windows; u; windows nt 5.1; en-gb; rv:1.8.1.6) gecko/20070725 firefox/2.0.0.6');     $res = curl_exec($con);     curl_close($con);