I started with some chilli seeds of varying types planted in some Gro-Sure Seed & Cutting compost (https://www.gardenhealth.com/product/grosure-seed-cutting-compost).
After a few weeks sitting on a heat map they started to appear. It was at this point I turned the grow lamp on for 12hrs a day as well with the lid down:
I watered once a day keeping the soil damp, but once the seedlings showed their first two leaves they wilted and looked pretty much dead or dying:
Any ideas would be much appreciated as to what I'm doing wrong... Maybe the lid shouldn't be on, or higher up... Maybe they can't breath, I don't know... I'd say inside the box it's warm, not hot, so I don't think it's too much heat, especially when its still quite cold at the moment in England UK (they are inside in my workshop).
Thanks for the comments guys, I've updated the setup now so that the seedlings (what's left) are outside..I have the grow light on from 0700 to 2200 with the heat matt coming on at 2200 to 0700:
