Can't change entity textures using Geckolib (Fixed)

I've been trying to add different varients to an entity, however the game keeps crashing when the texture is chosen for the entity. Inside the box for what I'm setting the texture to I have mymodid:textures/entities/mytexturename.png. If someone knows how to get this to work I would appreciate the help.

For people wondering instead of doing the whole link just put mytexturename without the .png