Ring Doorbell did not detect motion from a delivery

I received a notification from Amazon that a delivery was made. There was an Amazon envelope in front of my door, but my Ring Doorbell (2020 version) did not detect any motion. Any idea why this would happen? A short while later, my wife went out the from door and I was alerted.

Hi @DennisM. This could be because of how your Motion Frequency is set. Motion Frequency dictates how ofter your camera picks up motion. This is to help mitigate battery life. To optimize how to set your Motion Frequency, visit this Community article here.