> ## Documentation Index
> Fetch the complete documentation index at: https://docs.mangopay.com/llms.txt
> Use this file to discover all available pages before exploring further.

# 202001

> <small>&#8249; [All error codes](/errors/codes#klarna)</small>

<table>
  <tbody>
    <tr>
      <th class="header"><strong>Error message</strong></th>
      <td class="table-content">AdditionalData format error</td>
    </tr>

    <tr>
      <th class="header"><strong>Description</strong></th>
      <td class="table-content">The AdditionalData value is not the expected format, not complete, or not present.</td>
    </tr>

    <tr>
      <th class="header"><strong>Categories</strong></th>

      <td class="table-content">
        <div class="label">Pay-in</div>
      </td>
    </tr>
  </tbody>
</table>

#### Causes

This error occurs because the value of the `AdditionalData` parameter doesn't correspond to the serialized JSON object expected by Klarna for the extra merchant data.

#### What to do

Ensure the data you are sending is in line with:

* The guidance provided in the Klarna article about which objects to include
* The example structure provided in Klarna’s documentation

#### Example

In the example below, the Create a Klarna PayIn request was attempted with a valid JSON format for `AdditionalData`, but not the serialized object expected by Klarna:

```json theme={null}
{
    "Id": "wt_48f83ecc-e0e1-46bf-ab41-30c934bd2ad8",
    "Tag": "Created using the Mangopay API Postman collection",
    "CreationDate": 1706798077,
    "AuthorId": "213407540",
    "DebitedFunds": {
        "Currency": "EUR",
        "Amount": 1500
    },
    "CreditedFunds": {
        "Currency": "EUR",
        "Amount": 1200
    },
    "Fees": {
        "Currency": "EUR",
        "Amount": 300
    },
    "Status": "FAILED",
    "ResultCode": "202001",
    "ResultMessage": "AdditionalData format error",
    "ExecutionDate": null,
    "Type": "PAYIN",
    "Nature": "REGULAR",
    "CreditedWalletId": "213407543",
    "CreditedUserId": "213407540",
    "PaymentType": "KLARNA",
    "ExecutionType": "WEB",
    "ReturnURL": "http://www.mangopay.com/docs/please-ignore?transactionId=wt_48f83ecc-e0e1-46bf-ab41-30c934bd2ad8",
    "StatementDescriptor": "Mangopay",
    "Billing": {
        "FirstName": "Alex",
        "LastName": "Smith",
        "Address": {
            "AddressLine1": "6 rue de la Cité",
            "AddressLine2": "Appartement 3",
            "City": "Paris",
            "Region": "île-de-france",
            "PostalCode": "75003",
            "Country": "FR"
        }
    },
    "Shipping": {
        "FirstName": "Alex",
        "LastName": "Smith",
        "Address": {
            "AddressLine1": "Rue de la Fourche 26",
            "AddressLine2": "Appartement 3",
            "City": "Bruxelles",
            "Region": "Bruxelles-Capitale",
            "PostalCode": "1000",
            "Country": "BE"
        }
    },
    "LineItems": [
        {
            "Name": "Running shoes",
            "Quantity": 2,
            "UnitAmount": 400,
            "TaxAmount": 100,
            "Description": "ID of Seller 1"
        },
        {
            "Name": "Walking shoes",
            "Quantity": 1,
            "UnitAmount": 400,
            "TaxAmount": 100,
            "Description": "ID of Seller 2"
        }
    ],
    "Country": "FR",
    "Culture": "FR",
    "Email": "alex.smith@example.com",
    "Phone": "[+33][689854321]",
    "AdditionalData": "333333",
    "Reference": "1234"
}
```