Why is there an error when working with the autoposting plugin on Wodpress?

Question

PHP

I'm trying to send a test article to the autoposting plugin in Wordpress from ContentMonster
https://contentmonster.ru/setupexport

$token='тут мой токен';
$url='http://мойсайт.ru/wp-content/plugins/contentmonster/xr.php';
$post = [
                'key'         => $token,
        'method' => 'uploadPost',
                'title'       => '1111',
                'content'     => '111111111111111',
        'category_id' => '0',				
        'tags' => '11'
            ];	
$ch = curl_init($url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, $post);
$response = curl_exec($ch);
curl_close($ch);

Throws faultCode -32700 faultString parse error. not well formed
What to do?