Syntax error on decode, what's the problem?

Question

PHP

I get a response from the server https://ratings.utmn.ru/api/rating/?action=ratingd...

But when decoded, a syntax error occurs and outputs NULL
When viewed through the online json editor, everything is OK

$json = file_get_contents("https://ratings.utmn.ru/api/rating/?action=ratingdata&pageid=30bd2021-76a8-43ba-bee5-cf04c6ea5828");
$obj = json_decode($json);
var_dump($obj);