Pretty sure this is why its not working:
Exception during call reporting: System.Exception: Server returned a non successful status code - HTTPStatusCode=BadRequest - Reason= - Content={"code":"INVALID_QUERY","details":{"reason":"the field is not available for search","api_name":"Extension Number"},"message":"invalid query formed","status":"error"}
The thing is I have it setup with Extension number and when I look at the profile the extension number is there in Zoho so I am not sure why the field wouldn't be available for search