Caring for eggs

My geckos have layed eggs a few times now. But I cant seem to get the eggs to hatch. They tend to start to shrivel up and go moldy. Any help would be appreciated!

Sent from my SM-G950W using Tapatalk

Could you add a picture of the eggs, egg box, and incubator? What hatch media are you using? Do you mark the tops so you don't rotate them? What is the temperature and humidity of the egg box? These should help to answer your question.