400 INVALID_VALUE on POST /api/v2/outbound/contactlists despite valid CSV schema

NICE CXone API & Integrations
1

Trying to push a new contact list via the Outbound API. The payload structure matches the swagger spec exactly, but I keep hitting a 400 Bad Request with INVALID_VALUE.

Here is the JSON body I’m sending:

{
 "name": "Test_List_Pacific_1",
 "description": "Automated import test",
 "file": {
 "url": "https://s3.amazonaws.com/my-bucket/contacts.csv",
 "name": "contacts.csv"
 }
}

The CSV file is publicly accessible for testing. I’ve checked the file URL in a browser and it downloads fine. The content type is text/csv.

I’ve tried:

  1. Removing the description field. No change.
  2. Changing the name to something generic like “list1”. No change.
  3. Using a different CSV file with minimal columns (id, phone_number). Still fails.

The error response doesn’t give much detail:

{
 "errorCode": "INVALID_VALUE",
 "message": "Invalid value for request body"
}

Is there a hidden requirement for the S3 bucket policy or the file format that isn’t in the docs? Or is the file object structure wrong? I’ve been staring at this for an hour.