Error - N8N: ERRO: RequestError - Error: Argument error, options.body

Error - N8N: ERRO: RequestError - Error: Argument error, options.body.

Describe the problem/error/question

I’m facing a problem in my N8N where changing the response format to file returns the error: ERROR: RequestError - Error: Argument error, options.body.
When I change the response format to JSON, I can run the flow normally.
This is a flow to export evaluations in CSV format.

What is the error message (if any)?

Please share your workflow

In the Body Parameters, I'm using the following code:

{
  "include_header": true,
  "include_internal_response": true,
  "include_external_response": true,
  "include_risk": true,
  "use_published": false,
  "include_owner": true,
  "include_review_flag": true,
  "format": "csv",
  "include_progress_chart": true,
  "include_risks_triggered_chart": true,
  "include_confidential_footer": false,
  "assessment_ids": [
    {{$node["Extrair IDs-3"].json["assessment_id"]}}
  ]
}


Share the output returned by the last node

@Ana_larissa try turning off the JSON/RAW Parameters toggle and instead define each body param as individual key-value fields using the regular Body Parameters UI, then set Response Format back to File. the raw JSON string is what breaks when n8n tries to convert the body for a binary response — using structured fields avoids that serialization conflict entirely.