Games : Why won't the truffle NPC move in to my house In the above ground mushroom biome during hardmode

I unlocked hardmode by beating the wall of flesh. I have an above ground mushroom biome. I see the giant mushrooms in the background and I see mushroom biome monsters. I keep getting the notification that the truffle wants to move in and he won't. I have a house big enough I have torches, chairs, and a table. I know that there is no Crimson of corruption nearby because other NPCs have moved in.

Here is a picture of my above ground mushroom biome.