Make sure to use canned coconut milk. The thick, creamy texture will easily coat the cauliflower and allow the breading to stick. Also, make sure to use shredded coconut, not coconut flakes as those will be too large and may prevent the breading from sticking. If you can only find flakes or large shreds, pulse them in a food processor for a few seconds to break them down before adding them to the breading.