So I am trying to setup a test install of Horizon on a home lab so I can learn how it works. I built a 2012 R2 server, got the connection server installed, didn't use a security server or composer, not yet anyway. Set up my own CA and created the cert, got that error cleared up. So right now I have all greens in the Horizon admin console (except a yellow for event db, doesn't exist yet). Anyway, made some VMs, installed the agent, added them to Horizon, they show up fine, agent registers fine, I assigned one to myself, all looks good.
So when I try to connect to the Horizon server from a client, I see the pool I created, and when I click on it, it starts connecting to the VM, 2 devices just go to a black screen like its loading, another device actually shows a loading screen, but then says Session Disconnected when it hits about 25%.
Any idea what I've missed?