here is my request , but get error . i’m trying to created an invoice from this API.
from API documentation , i have try to get this. i’m wrong somewhere

<?
ini_set('display_errors', 1);
ini_set('display_startup_errors', 1);
error_reporting(E_ALL);

$currency=3;
$number=124560;
$billing_street="Lagos";

$curl = curl_init();
curl_setopt_array($curl, array(
    CURLOPT_URL => 'https://domain/api/invoices/',
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_ENCODING => "",
    CURLOPT_MAXREDIRS => 10,
    CURLOPT_TIMEOUT => 0,
    CURLOPT_FOLLOWLOCATION => true,
    CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
    CURLOPT_CUSTOMREQUEST => "POST",
    CURLOPT_POSTFIELDS => array(
        "customer_id" => 2180,
        "date" => $date,
        "currency" => $currency,
        "allowed_payment_modes" => array("1", "2", "3", "4", "5", "6"),
        "number" => $number,
        "subtotal" => $subtotal,
        "total" => $total,
        "billing_street" => $billing_street,
        "newitems" => array(
        
        
            
        [
     
       { "id": '1',
          "rel_id": "2",
          "rel_type": "invoice",
          "description": "12MP Dual Camera with cover",
          "long_description": "The JBL Cinema SB110 is a hassle-free soundbar",
          "qty": "2.00",
          "rate": "5.00",
          "unit": "CBM",
          "item_order": "1"
          }
          
          
          {
          "id": "2",
          "rel_id": "2",
          "rel_type": "invoice",
          "description": "CCTV CAMERA",
          "long_description": "hikvision full color camera",
          "qty": "1.00",
          "rate": "5.00",
          "unit": "",
          "item_order": "2"
          }
          
          
      ]
        
        
        
        ),
        
        
    ),
    CURLOPT_HTTPHEADER => array(
    "Authtoken:  eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1Ni0"
    ),
));
curl_exec($curl);
curl_close($curl);

?>

when trying i geting error, HTTP 500 Error , i’m new in json php . please i need your help

here is the api documentation https://perfexcrm.themesic.com/apiguide/#api-Invoices-PostInvoice