call to member function find on a non object

Question

I already checked older threads and there's no null value in my object.

Here in below code I am getting correctly page source in $html. And i checked that there is correct class names. This script was already working fine.

Now it gives error: Call to member function find() on a non-object

    function getParameter($url)
    {
        $root = new stdClass();
        $items = array();
        $items = array();
            $aContext = array(
                 'http' => array(
                 'proxy' => 'tcp://182.253.50.238:8080', // This needs to be the server and the port of the Proxy Server.
                 'request_fulluri' => true,
                 ),
                 );
            $cxContext = stream_context_create($aContext);
        $html = file_get_contents($url, false, $cxContext);
        echo $html;
        //$html = file_get_html($url);
        if($html)
        {
                $containers1 = $html->find('div.mapbox div.mapbox-text strong.street-address address'); //Gives error in this line
                }
 }