I don't know what's happening but whenever I do /skin set player NachoGGamer or using the menu from the mod it returns a different skin from the one I use, and also doesn't show my cape.

fabric server/ singleplayer 1.17
mine.ly/NachoGGamer.2

Mod currently uses an unofficial skin API. Migrating to mojang one is on the todo list :)

I checked the ely.by site and there is none that matches the one that shows up in game

Fixed in 6781b91