Journal Creation - Getting Error on C#

Journal Creation - Getting Error on C#

I am working on create Journal  on ZOHO, it always say   {"code":4,"message":"Invalid value passed for JSONString"}
My sample Json string,
[
  {
    "journal_date": "2013-09-04",
    "reference_number": "7355",
    "notes": "Loan repayment",
    "line_items": [
      {
        "account_id": "460000000000361",
        "description": "",
        "tax_id": "",
        "amount": "5000.00",
        "debit_or_credit": "credit"
      },
      {
        "account_id": "460000000038079",
        "description": "",
        "tax_id": "",
        "amount": "7000.00",
        "debit_or_credit": "credit"
      }
    ]
  },
  {
    "journal_date": "2013-09-04",
    "reference_number": "7356",
    "notes": "Monthly EMI",
    "line_items": [
      {
        "account_id": "360000000000361",
        "description": "",
        "tax_id": "",
        "amount": "25000.00",
        "debit_or_credit": "Credit"
      }
    ]
  },
  {
    "journal_date": "2013-09-05",
    "reference_number": "7865",
    "notes": "Client Payment",
    "line_items": [
      {
        "account_id": "360000000000361",
        "description": "",
        "tax_id": "",
        "amount": "52000.00",
        "debit_or_credit": "Debit"
      }
    ]
  }
]