Trees not being placed some of the time

I am working on a terrain that has a lot of foliage, and some of the time while painting trees none will be placed. This didn’t start happening until my foliage started getting pretty dense in places, BUT it doesn’t matter where I try to paint if it’s dense or sparse, sometimes just no trees or plants will spawn there. Sometimes if I try a different mesh it will spawn in other places some meshes will not. Sometimes it does get to a point where it will stop placing plants all together and I have to restart Unity. Any ideas to the cause or a solution to this problem?

There is a max amount allowed, maybe you are at it. Also check your density brush size - if your density is quite small and your brush size is huge, it won’t paint.