Facing zoho inventory rest api issue.

Facing zoho inventory rest api issue.

Dear sir/madam,

I am using the zoho inventory rest api. please check and suggest me as soon as possible.

Url : ' https://inventory.zoho.com/api/v1/purchaseorders?ignore_auto_number_generation=0?authtoken=f8d6e09ef3d90a4323f96aac7b2a667c&organization_id=647725867';

Request : data_json = '{
    "purchaseorder_number": "PO-00002",
    "date": "2015-05-28T00:00:00.000Z",
    "delivery_date": "2015-06-01T00:00:00.000Z",
    "reference_number": "REF-P-00002",
    "ship_via": "FedEx",
    "vendor_id": 4815000000044080,
    "salesorder_id": 4815000000044936,
    "is_drop_shipment": true,
    "is_inclusive_tax": false,
    "is_backorder": false,
    "template_id": 4815000000017003,
    "contact_persons": [
        "460000000026051"
    ],
    "attention": "Tony",
    "delivery_org_address_id": 4815000000044077,
    "delivery_customer_id": 4815000000044066,
    "notes": "Sample Note",
    "terms": "Terms and Conditions",
    "exchange_rate": 1,
    "line_items": [
        {
            "item_id": 4815000000044100,
            "line_item_id": 4815000000044897,
            "purchaseorder_item_id": 4815000000044892,
            "account_id": 4815000000035003,
            "name": "Laptop-white/15inch/dell",
            "description": "Just a sample description.",
            "item_order": 0,
            "bcy_rate": 122,
            "purchase_rate": 122,
            "quantity": 2,
            "quantity_received": 2,
            "unit": "qty",
            "item_total": 244,
            "tax_id": 4815000000044043,
            "tax_name": "Sales Tax",
            "tax_type": "tax",
            "tax_percentage": 12,
            "image_id": 2077500000000002000,
            "image_name": "dell.jpg",
            "image_type": "jpg"
        }
    ],
    "documents": [
        {
            "can_send_in_mail": true,
            "file_name": "sample.pdf",
            "file_type": "pdf",
            "file_size_formatted": "116.8 KB",
            "attachment_order": 1,
            "document_id": 16115000000096068,
            "file_size": 11957
        }
    ]
}';

$data_json = json_decode($data_json);

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_HTTPHEADER, array('Content-Type: application/json'));
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS,json_encode($data_json));
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$response  = curl_exec($ch);
curl_close($ch);

Response : {"code":4,"message":"Invalid value passed for JSONString"}