Earlier today, I was able to send snapshots to the Face API and get responses including faceAttributes describing emotion.
I'm using JavaScript via XMLHttpRequest.
Now, though I've not changed the code, I get OK 200 from the API calls, but the responseText and the response properties are both, "[]".
I'd like to troubleshoot to see what I'm doing wrong, but it seems like the only information available in the cognitive services portal relates to quota.
Where should I look for further analytics?
You'll get an empty response if the API does not detect a face in the image or if the image file is too large (>4MB). You can confirm by testing with an image you know previously worked. To get the best results, make sure the face is well-lit and all features are reasonably visible.