AnimationController does not move some bones

[changeno]

Hello. I’m currently trying to animate a pet which can walk using AnimationController, the animation is working in the animation editor but when I use a script to run the animation some of the bones do not move.

This is what it looks like inside the animation editor

As you can see, the animation is pretty detailed with all of the bones moving, as intended
However, when I playtest, the animation plays incorrectly with many of the bones not moving

This is my script which plays the animation

local humanoid = script.Parent:FindFirstChildOfClass("Humanoid")
humanoid:Destroy()
local animationController = Instance.new("AnimationController")
animationController.Parent = script.Parent

local animation = Instance.new("Animation")
animation.AnimationId = "http://www.roblox.com/asset/?id=12344657044"
local animationTrack = animationController:LoadAnimation(animation)

animationTrack:Play()

Any help is appreciated

[keremMCT (NETSTAL)]

Add Animator in the animation controller

[changeno]

Hey, thanks for the reply!
Unfortunately the issue is still occuring

[changeno]

UPDATE: Apparently I accidentally deleted something while importing the mesh which caused this issue. Now it works as intended.