PDF to Markdown API error: INVALID_REQUEST_FORMAT

Hi everyone,

I'm trying to test the following "PDF to Markdown" operation. Specifically, I'm using the API as follows:

curl --location 'https://pdf-services-ue1.adobe.io/operation/pdftomarkdown' \
--header 'X-API-Key: {KEY}' \
--header 'Authorization: Bearer {TOKEN}' \
--header 'Content-Type: application/json' \
--data '{
  "assetID": "urn:aaid:AS:UE1:88b99474-afee-4d97-97e3-47de96ed6c06",
  "getfigures": true
  }'

But I always get a 400 Band Request error with the following content:

{
    "error": {
        "code": "INVALID_REQUEST_FORMAT",
        "message": "Invalid request format."
    }
}