Unable to create Klarna payment - “Cannot create payment session for a disabled cash order” (403)

[vasilisdotme]

Hello team,

I’m encountering an issue while trying to integrate Klarna with Smart Checkout.

Here is an example request I’m sending:

POST /checkout/v2/orders

{
  "amount": 10000,
  "customerTrns": "D3000",
  "customer": {
    "email": "myemail@gmail.com",
    "fullName": "jhon doe",
    "phone": "+30690000000",
    "countryCode": "GR",
    "requestLang": "el"
  },
  "paymentTimeout": 1800,
  "preauth": false,
  "allowRecurring": false,
  "maxInstallments": 0,
  "paymentNotification": false,
  "tipAmount": 0,
  "disableExactAmount": false,
  "disableCash": true,
  "disableWallet": true,
  "sourceCode": "1111",
  "merchantTrns": "D3000",
  "tags": [],
  "klarnaOrderOptions": {
    "orderLines": [
      {
        "name": "Product  D3000",
        "quantity": 1,
        "unitPrice": 10000,
        "totalAmount": 10000,
        "merchantData": "Order: 325"
      }
    ]
  }
}

The response I receive is:

{
  "status": 403,
  "message": "OrdersValidationFailed: Cannot create payment session for a disabled cash order",
  "eventId": "5507"
}

If I set disableCash to false, the order is created successfully, but Klarna is not shown as a payment option during checkout.

Klarna is enabled on the account, and I have tested this both in demo and production, with the same result.

I would appreciate any guidance on what I might be missing or misconfigured.

Thank you in advance!

PS. I have followed the instructions here