签名原串：
POST
/v3/merchant/media/upload
1574046893
469d3cb02c1347e8a4b2ad6244e1e4a9
{"filename":"test.jpg","sha256":"61bfda6b7fc1fcae50fc69731423b69a73770fab382d3b1ed776554266f6042a"}
返回内容：
{
"code": "SIGN_ERROR",
"detail": {
"detail": {
"issue": "sign not match"
},
"field": "signature",
"location": "authorization",
"sign_information": {
"method": "POST",
"sign_message_length": 175,
"truncated_sign_message": "POST\n/v3/merchant/media/upload\n1574046893\n469d3cb02c1347e8a4b2ad6244e1e4a9\n{\"filena\n",
"url": "/v3/merchant/media/upload"
}
},
"message": "错误的签名，验签失败"
}
楼主我跟你一样的问题解决了吗
用签名验证工具，验证一下。对比参数，大小，转义等不能有一点问题的。
根据文档，仔细比对参数