System.Net.Http.HttpRequestException: Response status code does not indicate success: 404 (Not Found).
   at System.Net.Http.HttpResponseMessage.EnsureSuccessStatusCode()
   at System.Net.Http.HttpClient.GetByteArrayAsyncCore(HttpRequestMessage request, CancellationToken cancellationToken)
   at TencentSdk.Cos.Services.CosService.GetDataAsync(String region, String bucket, String filePathName, Int32 timeoutMilliSecs)
   at endoc.Application.DocAppService.GetCoverImage(String docId, Int32 width)
   at data.endoc.Web.Controllers.ImgController.GetCoverImage(String docId, Int32 width)