Change Cameras' Placement or Pointing Angle
Security cameras with built-in PIR motion sensor, such as Arlo cameras could see cameras do detect motion but fail to record or capture movement. Or cameras can't detect or record motions through glass or window glass panel.
In such cases,
avoid placing motion detection security cameras behind the glass window especially cameras with a PIR motion sensor;
do place wireless motion sensor security cameras closer to a WiFi router or hotspot.
The object from afar is relatively easier to be miss out, so don't expect security cameras to pick up every movement within its field of view. Focusing on strategic areas for motion detection helps achieve maximal peace of mind as well as
reducing unwanted false alarms.
https://reolink.com/security-camera-motion-detection-not-working/