goutte - Mink - Could not retrieve Microsoft served pages -

i have code

require_once(dirname(__file__) . '/../inc/mink.phar');  $url = 'http://some-asp-sites.com/';  // instantiate mink's goutte driver $guzzle_client_options = array(     'curl.options' => array(         'curlopt_ssl_verifypeer' => false,         'curlopt_certinfo' => false,         'curlopt_timeout' => 120             ),     'ssl.certificate_authority' => 'system' );  $client = new \behat\mink\driver\goutte\client(); $client->setclient(new \guzzle\http\client($url, $guzzle_client_options));  $driver = new \behat\mink\driver\gouttedriver($client);  // initialize mink $session = new \behat\mink\session($driver);  // start session $session->start();  // open form page $session->visit($url);  var_dump($session->getresponseheaders()); 

and when try using code on pages has part of response headers as

'server' =>      array       0 => string 'microsoft-httpapi/2.0' (length=21) 

then error

<h2>bad request - invalid header</h2> <hr> <p>http error 400. req...an invalid header name.</p> 

i have repeated code php served , microsoft served(i suspect asp) sites. asp sites has problem.

is there reason why shouldn't work microsoft served pages?