Missing texture in a custom item with geckolib plugin

Hello everyone! I was trying to add a simple gun to the game, i created the model and the texture in blockbench (I worked with Geckolib plugin for animations) and when i exported and try it on mcreator the object is bugged and the item is a square black and purple, can anyone help me out? I don't know what to do to, a follow a lot of tutorials but still don't work