@Balingsjes
Hi,
The problem may be related to your configurations and usage scenario. Please help confirm the following information about the issue.
1. Please go to the C420's Device Settings>Detection page and send me a picture of this page.
If the Wake-up Sensitivity is set to a low value, please set it higher. You can refer to the link below to learn what's the Wake-up Sensitivity.
What is the Wake-up Sensitivity of my battery camera/doorbell?
2. Please go to the Motion Detection page and send me a picture of it.
3. Can you share a picture of your camera's Live View page with us, and record the motion that can't be detected by the camera manually on the Live View page, then send it to me?
Best Regards