Bitrix gives an error Class 'CIBlockElement' not found in /home/c/ci ... How to solve?

Question

1C-Bitrix

Guys, help a newbie. I can’t solve the problem, or rather, I don’t even understand what the system doesn’t like.
There is a submenu in the section. I'm trying to edit it, but it gives me this error:
Fatal error: Class 'CIBlockElement' not found in /home/c/ci77777/public_html/services/.service1.menu.php on line 3

opened this file for editing and I don't understand what he wants. File code:
<?
$aMenuLinks = Array();
$rsSubMenu = CIBlockElement::GetProperty(1, 3, [], ['CODE'=>'SUB_MENU']);
$n = 0;
while($arSubMenu = $rsSubMenu->Fetch()){
if(empty($arSubMenu['VALUE'])) continue;
$aMenuLinks[$n][] = $arSubMenu['VALUE'];
$aMenuLinks[$n][] = $arSubMenu['DESCRIPTION'];

$n++;
}
?>
Please tell me where to dig, where to go?

Answer 1

you have this submenu implemented on the CIBlockElement::GetProperty infoblock property, i.e. this is someone's craft in which just regular functionality is not supported. I think most likely the menu items were added in PHP edit mode

In the properties of the "Services" infoblock, the "submenu" property has been added.
Having opened the list of added elements of the "Services" infoblock, I saw that each element has the ability to add /

Answer 2

\Bitrix\Main\Loader::includeModule('iblock');