A dream of Mandarin Cookies R3

The seeds have successfully fought their way through the first layer of soil and will now concentrate on root growth and slowly start to grow. Lamp is on 30% so it should be around 200ppfd after the seedlings stuck their heads out, it didn't take 2 days for them to just fall over. The temperature is 24 degrees with a humidity of 60-88% approx. i know that seedlings are sensitive, but to just fall over and die without touching them is really weird. i started 3 out of 5 seeds of the mandarin cookies r3 and unfortunately they all died. i hope the last two survive the seedling phase, i've never had any problems with the start, which is why i'm a little bit unsure what the reason is.