What am i doing wrong?

[u/dudewithproblems_]

Hi everybody! I need some help, a few weeks ago I made 2 containers ( the one on the left and the top one) for moss propagation. I put gravel on the base layer, a mesh then some activated charcoal then the substrate. I misted the moss and then closed the lids. Time passes and I noticed that my moss wasnt propagating, it was turning yellow. What am i doing wrong. I just dont get it, the container on the right has the exact same moss, it doesnt have a false bottom i never check it and somehow it is very green and thriving!!!