请求https://api.mch.weixin.qq.com/v3/applyment4sub/applyment/接口时报错，但是我获取了签名，不知道为啥提示错误的签名？

获取数据失败，请重试！https://api.mch.weixin.qq.com/v3/applyment4sub/applyment/System.Net.WebException: 远程服务器返回错误: (401) 未经授权。

   在 System.Net.HttpWebRequest.GetResponse()

  返回数据{“code”:“SIGN_ERROR”,“detail”:{“detail”:{“issue”:“sign not match”},“field”:“signature”,“location”:“authorization”,“sign_information”:{“method”:“POST”,“sign_message_length”:4556,“truncated_sign_message”:“POST\n/v3/applyment4sub/applyment/\n1633768376\nph12vkda.xdy\n{\“busine\n”,“url”:”/v3/applyment4sub/applyment/"}},“message”:“错误的签名，验签失败”}