Help with lxc containers

So I'm running on x86_64, and have successfully increased my image size to 32gb, and i believe i have installed all options needed to run lxc containers, but I am having difficulty launching them. It feels like it is not downloading the full image, because it completes very quickly when I click create, and when I press start, it stays with a red status.

I am looking to run some variant of Debian, preferably Ubuntu, so i can run a Unifi server on the same hardware as my routing platform. I have tried several different images from the list, and fell like I'm missing something. thanks for your help.