问微信小程序的对象存储，在上传图片时报错403，求助？

完全参考了 https://github.com/tencentyun/cos-wx-sdk-v5

存储对象上传的代码，其中nodejs端与后台计算签名已经ok（见图1）。但是实际在上传的时候报错，错误码为403。已将存储对象的权限设置为全部放开（见图4）

示例：

{"statusCode":403,"data":"<?xml version='1.0' encoding='utf-8' ?>\n<Error>\n\t<Code>AccessDenied</Code>\n\t<Message>Access Denied.</Message>\n\t<ServerTime>2019-04-08T17:57:36Z</ServerTime>\n\t<Resource>ctb-1253710041.cos.ap-guangzhou.myqcloud.com/wx7f5622edd9dfca38.o6zAJs5VsMgR3ymMJ0C5PWZ78QGY.vVEL5IyVKvfO34e204412a409ebde6c19fad28b73ec4.jpg</Resource>\n\t<RequestId>NWNhYjhiOTBfZjMxYjBiMDlfOTY1Y19iZmUyNmM=</RequestId>\n\t<TraceId>OGVmYzZiMmQzYjA2OWNhODk0NTRkMTBiOWVmMDAxODc0OWRkZjk0ZDM1NmI1M2E2MTRlY2MzZDhmNmI5MWI1OTQyYWVlY2QwZTk2MDVmZDQ3MmI2Y2I4ZmI5ZmM4ODFjYjEzMGU3N2I0OTJjYTAwYWExNjJhODI1NTRkOGZlM2Y=</TraceId>\n</Error>\n\n","header":{"Content-Type":"application/xml","Content-Length":"589","Connection":"close","Date":"Mon, 08 Apr 2019 17:57:36 GMT","Server":"tencent-cos","x-cos-request-id":"NWNhYjhiOTBfZjMxYjBiMDlfOTY1Y19iZmUyNmM=","x-cos-trace-id":"OGVmYzZiMmQzYjA2OWNhODk0NTRkMTBiOWVmMDAxODc0OWRkZjk0ZDM1NmI1M2E2MTRlY2MzZDhmNmI5MWI1OTQyYWVlY2QwZTk2MDVmZDQ3MmI2Y2I4ZmI5ZmM4ODFjYjEzMGU3N2I0OTJjYTAwYWExNjJhODI1NTRkOGZlM2Y="},"cookies":[],"errMsg":"uploadFile:ok"}

nodejs获取秘钥正常

权限ok

已加*号