I have started an aternos server with custom npcs. As I imported many skins to create more and more npcs with unique skins, I invited a few friends over. They keep telling me that most of the npcs have their textures missing. I gave them all the  skins they needed for the server, but even after refreshing, they still tell me that their textures are missing. I am aware that it might just be on their end and maybe they didnt put the skins in the wrong place, but i would like to know if downloading the skins is what my friends are meant to do in order to see all of these textures. Or does it have to do with all of the npcs being copied to the client side? As in a copied them only to me, and not on the server? I would really like to know.

The problem you are having is that only you have the skins downloaded, to fix it you can do two things, u can enter skins by a link of the skin or typing the name of a player to put their skin. Actually i don't know why that isn't working on my server, but you should try it, maybe the problem i'm having is because of another mod. Hope u got it.