The hides could not be that suitable for them if they are not going in them. What are the hides like? Pictures? I don't think the moss has anything to do with it, normally it won't bother the snakes. But to experiment, try taking out the moss from the hides and putting it around the enclosure.

Also, when I cannot get my humidity up I just make a moist hide. The moist hide has warm, damp paper towels in it. I also use this moist hide for my Leopard gecko since they need it.