DIAGNOSIS The detection zone is probably too broad and sensitive, and it's being triggered by light changes (like moving shadows from trees) or small pets.
FIX Open the camera in the Tapo app. Go to the Detection Settings. 1) First, adjust the Sensitivity slider down to a medium or low setting. 2) More importantly, use the Detection Zone tool. Draw a box on the live view to cover only the critical area (like a doorway), excluding windows where light changes and ceilings where bugs fly. Save the settings and test for a day.
IF THAT DIDN'T WORK Check if you have "Activity Zones" turned on but set incorrectly. Also, look for an option called "Detection Interval" or "Cool Down Time" and set it to at least 30 seconds. This prevents it from sending a new alert for the same ongoing motion every 5 seconds.
HEADS UP The C200 uses pixel changes to detect motion, not a separate sensor. Anything that changes the image significantly—a large shadow, a light turning on/off, a curtain blowing—can trigger it. Fine-tuning the zone is the most effective tool you have.