SoapClient constructor works with 7.1, fails with 7.2

My SoapClient constructor works in 7.1 but fails in 7.2 returns an error

 [message:protected] => SOAP-ERROR: Parsing WSDL: 
 Couldn't load from 'https://domain/url.svc?singleWsdl' : failed to load external entity

The WSDL URI appears to be legitimate. I can call it from a browser and get a WSDL document back. Any ideas for what to look at?

    $opts = array(
            'ssl' => array(
            'ciphers' => 'RC4-SHA',
            'verify_peer' => false,
            'verify_peer_name' => false
        )
    );

    $params = array(
        'encoding' => 'UTF-8',
        'verifypeer' => false,
        'verifyhost' => false,
        'soap_version' => SOAP_1_1,
        'trace' => 1,
        'exceptions' => 1,
        'connection_timeout' => 180,
        'stream_context' => stream_context_create($opts)
    );

    try {

        $this->_client = new SoapClient($wsdl, $params);

The appropriate libraries are enabled in PHP 7.2

[PHP_OPENSSL]
extension=php_openssl.dll
[PHP_SOAP]
extension=php_soap.dll