I have got the following offer:

{
    "total": 1,
    "size": 1,
    "href": "\/sell\/inventory\/v1\/offer?offset=0&limit=20",
    "limit": 20,
    "offers": [
        {
            "offerId": "5031671010",
            "sku": "TEST_KINECT",
            "marketplaceId": "EBAY_DE",
            "format": "FIXED_PRICE",
            "listingDescription": "Sielekonsole mit Kabeln und Datentr\u00e4ger",
            "availableQuantity": 4,
            "pricingSummary": {
                "price": {
                    "value": "789.12",
                    "currency": "EUR"
                }
            },
            "listingPolicies": {
                "paymentPolicyId": "100677191011",
                "returnPolicyId": "100677190011",
                "fulfillmentPolicyId": "100677194011"
            },
            "categoryId": "139971",
            "merchantLocationKey": "TEST_KOELN",
            "status": "UNPUBLISHED"
        }
    ]
}

When I try to publish this offer using a POST on https://api.ebay.com/sell/inventory/v1/offer/5031671010/publish I got the following error:

{
    "errors": [
        {
            "errorId": 2003,
            "domain": "ACCESS",
            "category": "APPLICATION",
            "message": "Internal error",
            "longMessage": "There was a problem with an eBay internal system or process. Contact eBay developer support for assistance",
            "parameters": [
                {
                    "name": "code",
                    "value": "415"
                }
            ]
        }
    ]
}