Why is Microsoft Cognitive Face not working?

Question

C++ / C#

I'm trying to write a Xamarin program that detects faces in a photo I just took, but calling DetectAsync throws a NullReferenceException in that part of the code. What could be the problem?

using (Stream imageFileStream = new MemoryStream(a))
                {
                    imageFileStream.Position = 0;
                    var result = await faceServiceClient.DetectAsync(imageFileStream);

                    if (result != null)
                        await BlobStorageService.SaveBlockBlob("photos", a, Entry1.Text);
                }

Where a is the byte array of the image.

Answer 1

You need to look for the reason in "a - array of bytes of the image."