问RecordCreate接口报AuthFailure 4100 什么原因？

$srcStr = "GETcns.api.qcloud.com/v2/index.php?Action=RecordCreate&domain=travelagentsupport.com&Nonce=17250&recordLine=默认&recordType=A&SecretId=AKID88waP5szFUwHQXuk4GBvXzFD1g9RcWJu&SignatureMethod=HmacSHA256&subDomain=wen&Timestamp=1580977932&value=xx.xx.xx.xx";

$signStr = base64_encode(hash_hmac('sha256', $srcStr, $secretKey, true));

$signature=urlencode($signStr);

得到签名为：FX9li5Pg5VbzzFa35Des0A8HUOv4SIdN4gHKe50Q17Q%3D

$url = https://cns.api.qcloud.com/v2/index.php?Action=RecordCreate&domain=travelagentsupport.com&Nonce=17250&recordLine=默认&recordType=A&SecretId=AKID88waP5szFUwHQXuk4GBvXzFD1g9RcWJu&Signature=FX9li5Pg5VbzzFa35Des0A8HUOv4SIdN4gHKe50Q17Q%3D&SignatureMethod=HmacSHA256&subDomain=wen&Timestamp=1580977932&value=42.120.226.13

$send=$this->httpGet($url); //发请求

$res=json_decode($send);

最后返回4100，AuthFailure 我都是按照官方文档说的操作的，居然签名失败？什么原因？