Geckolib mods can't load when exported to Minecraft

Hi, I was learning Geckolib animations on Mcreator and I was following this video

https://www.youtube.com/watch?v=8xBrPlE6QLs&ab_channel=CatBro

I followed everything as shown in the video and when I test run the mod in Mcreator, everything works perfectly fine.

However, when I export the exact same mod into a .jar file and install it into Minecraft, it crashes at the loading screen.

Here's the image of what happens. I tried to search for a solution but couldn't find any.

https://imgur.com/3k6ULCm

Any suggestion would be much appreciated