DocuSign REST API向现有信封中添加新收件人

Question

我需要将新收件人添加到现有的草稿信封中。

但是，我从DocuSign API收到400个错误的请求响应。

我在做什么错了？

我正在发送以下请求

url = "https://demo.docusign.net/restapi/v2/accounts/" + accountID + "/envelopes/" + envelopID + "?advanced_update=true"; 

REST API代码以添加新的收件人。

{
    "status": "sent",
    "recipients": {
        "signers": [{
            "email": "amith@gmail.com ",
            "name": "Sara Mac",
            "recipientId": "3",
            "tabs": {
                "signHereTabs": [{
                    "anchorString": "S1P300",
                    "anchorXOffset": "1",
                    "anchorYOffset": "1",
                    "anchorIgnoreIfNotPresent": "true",
                    "documentId": "2",
                    "pageNumber": "1"
                }]
            }
        }]
    }
}