没有在PHP中使用xpath的类而无法获取img

My code is:

<?php 

    $DomDocument = new DOMDocument();
    $DomDocument->preserveWhiteSpace = false;
    $DomDocument->load($URLToFetch);

    $xpath            = new DomXpath($DomDocument);
    $divContainingImg = $xpath->query('//*[@class="n-car_preview__first"]');

    $imgHTMLCode      = $divContainingImg->item[0]->value;

?>

But when I try to output the code I am expecting everything from the div in which the img tag is, however, I am getting this errror:

Warning: DOMDocument::load(): Specification mandate value for attribute itemscope

I want to grab the first img tag inside of the div with that class n-car_preview__firstbut it's not happening. any idea what could be wrong?

The HTML looks like this:

<div class="n-car_preview__first">

    <img src="http://example.org/image-test.jpg" alt="Test image" width="320" height="240">

</div>