Replace Smart Object (smartObject) API internal error when processing

Hi, I want to replace a smart object in a layer of my PSD file with a png image the same size as the layer to be replaced. But I get an Internal Error message.

I make a POST to https://image.adobe.io/pie/psdService/smartObject 

with this json:

{
  "inputs": [
    {
      "storage": "external",
      "href": "myurlpath/7043086_522_c.psd"
    }
  ],
  "options": {
    "layers": [
      {
        "name": "SmartObject",
        "locked": true,
        "visible": true,
        "add": {
          "insertAbove": {
            "id": 0,
            "name": "string"
          },
          "insertBelow": {
            "id": 0,
            "name": "string"
          },
          "insertInto": {
            "id": 0,
            "name": "string"
          },
          "insertTop": true,
          "insertBottom": true
        },
        "input": {
          "storage": "external",
          "href": "myurlpath/Files/imagen_para_reemplazar1.jpg"
        },
        "bounds": {
          "height": 4,
          "left": 0,
          "top": 0,
          "width": 4
        }
      }
    ]
  },
  "outputs": [
    {
      "href": "https://www.dropbox.com/myoutputpath",
      "storage": "dropbox",
      "width": 0,
      "type": "image/tiff",
      "overwrite": true,
      "quality": 0,
      "compression": "small"
    }
  ]
}

Both files are accesible. I tryied with a wrong filename and it give me another error, so It seems the files are found. The layer to be replaced is called "SmartObject"

When looking at status API I get this error

           "errors": {
                "code": 500,
                "title": "Internal Service Error",
                "type": "InternalServiceError"
            }