I addition to what ceedee said, if it’s internal fogging, you won’t be able to wipe it off with a soft cloth. Try that, if it goes, it’s external, not faulty, and you will have to look to other solutions. A little spit on the lens, polished off can work, but there are many anti fogging products on the market that would most likely be effective. I use sea drops, Works for around two months then needs redoing. Only one of my seven cameras is affected. It’s low, and points in the worst direction, and is not under the eves, like the others. If I swap them around, the location always has the problem, not the camera.