Sales Invoice Api [Bad Request 'Server error' ]

,

I’m trying to make a new sales invoice using the api but every time it returns Server Error with no error messages
This is my request (I’m sending all the required parameters ) :
url : ******.erpnext.com/api/resource/Sales Invoice
parameters :

{
	"selling_price_list": "Standard Selling",
	"items": [{
		"item_group": "Products",
		"base_price_list_rate": 3,
		"image": "/files/suger1kilo (1).jpg",
		"creation": "2017-02-12 15:26:29.537249",
		"base_amount": 6,
		"qty": 2,
		"margin_rate_or_amount": 0,
		"rate": 3,
		"owner": "ahakim@panarab-media.com",
		"cost_center": "Main - PAM",
		"actual_qty": 98,
		"base_net_amount": 6,
		"so_detail": "cc8e94c158",
		"modified_by": "ahakim@panarab-media.com",
		"base_net_rate": 3,
		"discount_percentage": 0,
		"item_name": "Sugar",
		"sales_order": "SO-00002",
		"amount": 6,
		"net_rate": 3,
		"stock_uom": "Unit",
		"warehouse": "Finished Goods - PAM",
		"docstatus": 1,
		"actual_batch_qty": 0,
		"description": "Sugar",
		"parent": "SINV-00001",
		"brand": "",
		"base_rate": 3,
		"item_code": "Sugar",
		"margin_type": "",
		"page_break": 0,
		"doctype": "Sales Invoice Item",
		"delivered_qty": 0,
		"delivered_by_supplier": 0,
		"price_list_rate": 3,
		"name": "ad131466e8",
		"idx": 1,
		"item_tax_rate": "{}",
		"income_account": "Sales - PAM",
		"modified": "2017-02-12 15:27:30.590015",
		"expense_account": "Cost of Goods Sold - PAM",
		"parenttype": "Sales Invoice",
		"is_sample_item": 0,
		"net_amount": 6,
		"total_margin": 0,
		"is_fixed_asset": 0,
		"parentfield": "items"
	}],
	"price_list_currency": "EGP",
	"base_net_total": 38.5,
	"debit_to": "Debtors - PAM",
	"conversion_rate": 1,
	"company": "PAm",
	"grand_total": 38.5,
	"posting_date": "2017-03-19",
	"naming_series": "SINV-",
	"currency": "EGP",
	"base_grand_total": 38.5,
	"due_date": "2017-03-19",
	"plc_conversion_rate": 1,
	"customer": "Moustapha-Customer",
	"Status": "Paid",
	"doc_status": 1
}

How are you calling apis?

Bad Request 'Server error' seems issue with input data.

it returns the issue when there is an issue with input data