After migrating to PHP 5.6.5, the soap 1.2 did not work anymore. So I solved the problem by adding optional parameters SSL.
My error: failed to load external entity
How to solve:
// options for ssl in php 5.6.5
$opts = array(
'ssl' => array('ciphers'=>'RC4-SHA', 'verify_peer'=>false, 'verify_peer_name'=>false)
);
// SOAP 1.2 client
$params = array ('encoding' => 'UTF-8', 'verifypeer' => false, 'verifyhost' => false, 'soap_version' => SOAP_1_2, 'trace' => 1, 'exceptions' => 1, "connection_timeout" => 180, 'stream_context' => stream_context_create($opts) );
$oSoapClient = new SoapClient ( $url . "?WSDL", $params );