Floodlight cam does not alert when person walk by consistently

Hello all, I am new to this. I have purchased a floodlight cam wired plus. I have everything set up, wifi is good all of my set up are good, checked and re checked. I can see the person walking by clearly and no sensors alarms go on 75 % of the time.  25% works, I can be right in front of the camera at 8 feet and it does not pick me up, does not pick up the truck or quad getting in the yard. At this time this is pretty useless. I did a reboot, all the health check are good. I have checked with a friends who has the same and at this point we are lost on why this is not working???? Help please!