What can I do to fix broken textures?

I recently started using MCreator to make a simple mod for me and my friends to use on our server. I tried making a tophat in Blockbench and it looked normal, but when I saw it ingame, the Textures were completely messed up.

Blockbench: https://cdn.discordapp.com/attachments/755832430996226119/811883339580440586/Screenshot_86.png

Ingame: https://cdn.discordapp.com/attachments/755832430996226119/811883383968890880/Screenshot_88.png

Is there any way to fix this? (The mod is for the 1.16 btw)