I have three problems with eBay sandbox.

1.

Whenever I want to publish an offer I get the following message:

The eBay listing associated with the inventory item, or the unpublished offer has invalid data in the associated Fulfillment policy. Specify at least one valid shipping service.

I know that it’s been working wrong since the policy I use for offer has a shipping service. Shipping service has been specified, but this message keeps showing. Also, publishing offers was working until a few days ago.

2.
When I want to fetch my created fulfillment policy I get the following response:

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

I only get successfull response for only one policy and I can’t update that policy or delete it. When I want to update with the body below, I get the response that is below body.
Request body:

{
    "categoryTypes": [
        {
            "name": "ALL_EXCLUDING_MOTORS_VEHICLES"
        }
    ],
    "handlingTime": {
        "unit": "DAY",
        "value": 3
    },
    "localPickup": false,
    "marketplaceId": "EBAY_DE",
    "name": "standardversand",
    "shippingOptions": [
        {
            "costType": "FLAT_RATE",
            "insuranceFee": {
                "currency": "EUR",
                "value": "0.00"
            },
            "insuranceOffered": false,
            "optionType": "DOMESTIC",
            "packageHandlingCost": {
                "currency": "EUR",
                "value": "0.00"
            },
            "shippingServices": [
                {
                    "buyerResponsibleForShipping": false,
                    "freeShipping": false,
                    "shippingCarrierCode": "DHL",
                    "shippingServiceCode": "DE_DHLPaket",
                    "shippingCost": {
                        "currency": "EUR",
                        "value": "5.90"
                    },
                    "shippingService": "DE_DHLPaket"
                }
            ]
        }
    ]
}

Response:

{
    "errors": []
}

I expected my offer to be published. I tried deleting, getting and modifying fulfillment policy but it didn’t help.