My 12 week old Min Pin will not stop pooping in her Kennel.?

It started with her peeing in her kennel, which I understood she has a small bladder and cant hold it for long. But recently she started pooping in there. Every single night she uses the poops in her kennel, and then just lays in it. She doesn't whine to let us know she has to go or anything. Also I will stand outside urging her to go potty for 30-40 minutes, right before going to bed. She constantly gets distracted, and just sniffs around. It drives me crazy, because I have to clean her kennel constantly, and I am going through a zillion towels. every time she does it, I do stick her nose in it and tell her no very harshly, and then take her out. Every time she poops outside I give her a lot of praise. What can I do to make her stop?