eBay API 500 Internal Server error when posting payment policy

Question

I am trying to post an item on ebay through their API.

I have successfully added a product to inventory, created a fulfillment and return policy. I am adding the payment policy through their API explorer the same as for inventory, fulfillment and return policy. But when I want to add payment policy I get error 500 internal server error.

The JSON code is similar to the one posted in the documentation: https://developer.ebay.com/api-docs/sell/account/resources/payment_policy/methods/createPaymentPolicy

Payment policy POST URI https://api.sandbox.ebay.com/sell/account/v1/payment_policy

The returned error:

{
"errors": [
  {
   "errorId": 20500,
   "domain": "API_ACCOUNT",
   "category": "APPLICATION",
   "message": "System error."
  }
]
}

The JSON that i want to post:

{
  "name": "TestPolicy___",
  "description": "Vehicle payment policy, 500€ down, full in 7 days",
  "marketplaceId": "EBAY_DE",
  "categoryTypes": [
   {
    "name": "MOTORS_VEHICLES",
    "default": true
   }
  ],
 "paymentInstructions": "A PayPal deposit of 500€ is due in 48 hours, payment in full is due in 7 days.",
 "fullPaymentDueIn": {
   "value": 7,
   "unit": "DAY"
 },
 "deposit": {
   "amount": {
     "value": "500.00",
     "currency": "EUR"
   },
   "dueIn": {
     "value": 48,
     "unit": "HOUR"
   }
 },
 "paymentMethods": [
   {
    "paymentMethodType": "MONEY_ORDER"
   },
   {
    "paymentMethodType": "CASHIER_CHECK"
   },
   {
    "paymentMethodType": "CASH_ON_PICKUP"
   }
  ]
 }
}

So after a few tries I noticed that I can post this JSON code to the EBAY_DE store without an error.

{
           "name": "___TestPolicy",
           "description": "Vehicle payment policy, $500 down, full in 7 days",
           "immediatePay": true,
           "marketplaceId": "EBAY_US",
           "categoryTypes": [
             {
               "name": "ALL_EXCLUDING_MOTORS_VEHICLES",
               "default": true
             }
           ],
           "paymentInstructions": "A PayPal deposit of $500 is due in 48 hours, payment in full is due in 7 days."
        }

But when I try to post the same code on EBAY_US, I get an error saying PAYMENT_METHODS_NOT_FOUND.

Does anyone have any idea why EBAY_US needs the PAYMENT_METHODS_NOT_FOUND parameter but EBAY_DE doesn't?

Error when I want to post on EBAY_US:

{
   "errors": [
     {
       "errorId": 20403,
       "domain": "API_ACCOUNT",
       "category": "REQUEST",
       "message": "Disabled.",
       "longMessage": "Invalid payment detail",
       "inputRefIds": [
         null
       ],
       "parameters": [
         {
           "name": "PAYMENT_METHODS_NOT_FOUND",
           "value": "Payment Methods not found for the given request Criteria"
         }
       ]
     }
   ]
}