Bulk Write API problem with "Upsert" find_by - Id

Bulk Write API problem with "Upsert" find_by - Id

I'm trying to do an upsert upload using Zoho CRM Bulk Write API following the documentation: Bulk Write API
On the second step where I need to create a Bulk write job, I got the following error message:
  1. {"status":"error","code":"INVALID_FIELD_NAME","message":"invalid mapping. invalid api_name find_by - Id.","details":{}}
I'm just testing with my application, and using a Free Edition account.
The error was not listed on the possible errors on Bulk Write API documentation so I couldn't troubleshoot it correctly.

Here is part of the data I'm trying to upsert,:
  1. Module: Leads
  2. Id,Last_Name,Email,Company
    4788189000000474102,"""Kitzman (Sample)""",chau-kitzman@gmail.com,"""Creative Business Systems""
    4788189000000474103","""Frey (Sample)""",theola-frey@frey.com,"""Dal Tile Corporation""
    4788189000000474104","""Ruta (Sample)""",michael-gruta@cox.net,"""Buckley Miller & Wright""

Please advice.
Thanks!