Notification but nobody

Just installed the wired doorbell. This morning I got the doorbell notification, human, but when I played the video, there was nothing, not even a bird. I can understand a false positive with the motion detector, but not with the human setting. Any thoughts?
Thank you.

Hi, not sure if you have sorted this yet, but I only got mine yesterday, and found using the app a little confusing, though at 79 I am not exactly phone savvy.
Anyway I had a similair problem, but found I was looking in the wrong place, the “events” tab is where where it all happens and shows motion detections, and there were a few of me looking at it :o)