Unable to update categories of a document

[Pierrick Puimean Chieze]

I am trying to update the categories of a document, using Swagger (more specifically, using this method, but I get a malformed Json error with a 400 status code.

Request URL

https://api.shoeboxed.com:443/v2/accounts/1809343498/documents/58779bd28850c1bc73f20f4a/

Request Body (as pasted in swagger)

{
  "categories": [
    "Office"
  ]
}

Response Body

{
  "code": "MALFORMED_JSON_ERROR",
  "reason": "The HTTP message body couldn't be parsed as JSON.",
  "details": []
}

I am quite lost here, because the JSON pasted seems to be correctly formatted.