Any ideas why my Wyze cam is missing activity?

I have a Wyze cam with SD card, it was working beautifully a month ago when I first installed it. It captured all activity on my front porch- which is the goal. But now, while it seems to be triggered by every single car that drives by, its not picking up people actually walking through the driveway and onto the porch. Any ideas why the motion detection isn’t working? I have played with the zones, without different results.