Why is the XPath query not working correctly?

Question

PHP

I parsed the search results for the library directory . Now we need to extract the necessary data from it. To begin with, at least find the number of divs with the searchrez class in the div with the searchrezult ID :

In the source, the structure is the same as in the console:

But instead of 4, 0 is displayed:

echo $xpathSKBM->query('//div[@id="searchrezult"]/div[@class="searchrez"]')->length;

Help me please.
Whole code:

$bookTitle = 'Код Дурова';

require '../vendor/autoload.php';

use GuzzleHttp\Client;

// Инициализируем класс для работы с удалёнными веб-ресурсами
$client = new Client();

// Делаем запрос на страницу выдачи, получаем ответ
$response = $client->request('POST', 'http://skbm.nekrasovka.ru/request', [
    'form_params' => [
        '_service' =>'STORAGE:opacfindd:IndexView',
        '_action' => 'php',
        '_errorhtml' => 'error1',
        '_handler' => 'search/search.php',
        'querylist' => '<_service>STORAGE:opacfindd:FindView[separator]<_version>2.5.0[separator]<session>26026[separator]<_start>0[separator]<start>0[separator]<$length>15[separator]<length>15[separator]<iddb>1[separator]<_showstr><i>Заглавие</i> '.$bookTitle.'[separator]<_str>[bracket]TITL '.$bookTitle.'[/bracket][separator]<$outform>SHORTFM[separator]<outformList[0]/outform>SHORTFM[separator]<outformList[1]/outform>LINEORD[separator]<outformList[2]/outform>SHORTFMS[separator]<outformList[3]/outform>SHORTFMSTR[separator]<$filterstr>[bracket][bracket]LRES [apos]ТЕКСТЫ[apos][/bracket][/bracket] AND [bracket]LPUB [apos]КНИГИ[apos][/bracket][separator]<$filtersids>filter_1_2_0[END]filter_1_3_0[separator]<$fshowstr><i>вид документа</i> тексты И <i>вид издания</i> книги[separator]<query/body>(TITL '.$bookTitle.') AND ((LRES \'ТЕКСТЫ\')) AND (LPUB \'КНИГИ\')[separator]<_history>yes[separator]<userId>ADMIN[separator]<$linkstring>043[ID]Заказ документа[END]044[ID]Заказ копии документа[END][separator]<level[0]>Full[separator]<level[1]>Retro[separator]<level[2]>Unfinished[separator]<level[3]>Identify[separator]<$swfterm>[bracket]TITL '.$bookTitle.'[/bracket] AND [bracket][bracket]LRES [apos]ТЕКСТЫ[apos][/bracket][/bracket] AND [bracket]LPUB [apos]КНИГИ[apos][/bracket][separator]<_iddb>1[separator]<$addfilters>[NEXT]filter_1_1_else[IND]fixed_1_0_1525854941893[CLASS](LFR \'печатная/рукописная\')[TEXT]печатная/рукописная[separator]<$typework>search[separator]<$basequant>2391872[separator]<$flag45>yes',
        '_numsean' => '26026'
    ]
]);

// Выводим нужное из хтмла выдачи
$htmlSKBM = $response->getBody();
$docSKBM = new DOMDocument();
@$docSKBM->loadHTMLFile($htmlSKBM);

$xpathSKBM = new DOMXpath($docSKBM);
echo $xpathSKBM->query('//div[@id="searchrezult"]/div[@class="searchrez"]')->length;