Cannot load the AnimationClipProvider Service?

I'm making a gun that loads animations, and when I first use the gun, the animations work fine. However, when I reset and use the gun again, the animations don't work and instead throw me an error. I've looked everywhere on the internet for the same issue and they don't work for me.

The error is on a ModuleScript, and is on this line:

local animTrack = animator:LoadAnimation(animation)

If the whole script helps then:

local gunScripts = {}

gunScripts.PistolScript = function(GunName)
	--Variables
	local runService = game:GetService("RunService")
	local UIS = game:GetService("UserInputService")
	local player = game.Players.LocalPlayer
	local mouse = player:GetMouse()
	local char = workspace:WaitForChild(player.Name)
	local gun = player:WaitForChild("Backpack"):WaitForChild(GunName) or player.Character:WaitForChild(GunName)
	local playerGui = player:WaitForChild("PlayerGui")
	local mobileReloadGui = playerGui:WaitForChild("MobileReloadGui")
	local mobileReloadButton = mobileReloadGui:WaitForChild("ReloadButton")
	local ammoGui = playerGui:WaitForChild("AmmoGUI")
	local ammoText = ammoGui.Background.AmmoText
	local gunLabel = ammoGui.GunLabel
	local ReloadGui = playerGui:WaitForChild("ReloadGui")
	local reloadText = ReloadGui.ReloadText
	local rs = game:GetService("ReplicatedStorage")
	local re = rs:WaitForChild("Events"):WaitForChild("ShootEvent")
	local weaponInfo = require(rs.Modules.WeaponInfo)
	local gunIndex = weaponInfo:GetWeaponByName(GunName)
	local debounce = false
	local firerate = gunIndex.Firerate
	local GunAnimations = rs.GunAnimations
	local animator = player.Character.Humanoid:FindFirstChild("Animator")
	local ammoAmount = gunIndex.Ammo
	local connection

	local firing = false
	
	runService.Heartbeat:Connect(function()
		ammoText.Text = "Ammo: "..ammoAmount.."/"..gunIndex.Ammo
	end)
	
	if not UIS.KeyboardEnabled then
		gun.Equipped:Connect(function()
			if ammoAmount < gunIndex.Ammo then
				mobileReloadGui.Enabled = true
			end
		end)
		
		gun.Unequipped:Connect(function()
			mobileReloadGui.Enabled = false
		end)
		
	mobileReloadButton.MouseButton1Click:Connect(function()
			local reloadDebounce = false
			
			if reloadDebounce then return end
			reloadDebounce = true
			local reloadAnim = GunAnimations:WaitForChild("PistolReload")

			local reloadTrack = gunScripts.loadAnimation(animator, char:FindFirstChildWhichIsA("Humanoid"), reloadAnim)
			reloadTrack:Play()
			local reloadSound = gun:WaitForChild("ReloadSound")
			reloadSound:Play()

			local isUnequipped = false

			gun.Unequipped:Connect(function()
				isUnequipped = true
				if reloadTrack.IsPlaying then
					print("stopped")
					reloadTrack.TimePosition = 0
					reloadTrack:Stop()
					reloadSound:Stop()
					reloadDebounce = false
				end
			end)
			

			reloadTrack.Ended:Connect(function()
				if not isUnequipped then
					print("reloaded")

					ammoAmount = gunIndex.Ammo
					print("ammount = 19")
					ReloadGui.Enabled = false
					reloadDebounce = false
				end
			end)
		end)	
	end

	function gunScripts.loadAnimation(animator, humanoid, animation)
		if not animator then
			animator = Instance.new("Animator")
			if humanoid.Parent.Parent == nil then
				repeat task.wait(1) until humanoid.Parent.Parent == workspace
			end
			animator.Parent = humanoid
		end
		
		print("Parent: "..humanoid.Parent.Name)
		print("Animator: "..animator.Name)
		print("Animation: "..animation.Name)
		local animTrack = animator:LoadAnimation(animation)
		print(animTrack)
		return animTrack
	end

	--When activated, it will fire remote event.
	function gunScripts.onActivated()
		--If the equip animation is done and if the player has more than 0 ammo then...
		if gun:GetAttribute("PlayedEquipAnimation") and ammoAmount > 0 then
			--The shooting animation for the gun.
			local shootAnim = GunAnimations.PistolShoot
			--If the character's humanoid does not have a humanoid to load animations in then: 
			local shootTrack = gunScripts.loadAnimation(animator, char:FindFirstChildWhichIsA("Humanoid"), shootAnim)
			shootTrack:Play()

			--Sets the target of the player's gun to the mouse's target.
			local params = RaycastParams.new()

			params.FilterDescendantsInstances = {
				gun,
				player.Character
			}
			params.FilterType = Enum.RaycastFilterType.Exclude
			params.IgnoreWater = true

	
			local mouseRay = game.Workspace.Camera:ScreenPointToRay(mouse.X, mouse.Y)
			local origin = mouseRay.Origin
			local direction = mouseRay.Direction * 500

			local result = workspace:Raycast(origin, direction, params)
			local target = nil

			if result and result.Instance then
				target = result.Instance
			end
			print(target)
			--Fires a remote event to damage the enemy.
			re:FireServer(target, result)
			--Subtracts the ammo amount variable by 1.
			ammoAmount -= 1
			--Sets the GUI text to display the amount of ammo.
			ammoGui.Background.AmmoText.Text = "Ammo: "..ammoAmount.."/"..gunIndex.Ammo
			--If the ammo amount is 0, however, then the reloadGUI displays.
			if ammoAmount == 0 then
				ReloadGui.Enabled = true
			end
		end
	end

	
	--When the gun is equipped then,
	gun.Equipped:Connect(function()
		print("equipped")
		--The display text for the gunGUI displays the gun's name.
		gunLabel.Text = gun.Name
		--Allows the player to see the ammoGUI
		ammoGui.Enabled = true
		--if ammo amount is 0 then
		if ammoAmount == 0 then
			--The player can see the reload gui
			ReloadGui.Enabled = true
		end

		--The equip animation.
		local equipAnim = GunAnimations:WaitForChild("PistolEquip")

		local equipAnimTrack = gunScripts.loadAnimation(animator, char:FindFirstChildWhichIsA("Humanoid", true), equipAnim)
		equipAnimTrack.Looped = false
		equipAnimTrack:Play()
		gun:SetAttribute("PlayedEquipAnimation", false)

		equipAnimTrack.Ended:Connect(function()
			gun:SetAttribute("PlayedEquipAnimation", true)
		end)

		local holdAnim = GunAnimations:WaitForChild("PistolHold")

		local holdAnimTrack = gunScripts.loadAnimation(animator, char:FindFirstChildWhichIsA("Humanoid", true), holdAnim)
		holdAnimTrack.Priority = Enum.AnimationPriority.Action
		holdAnimTrack.Looped = true
		holdAnimTrack:Play()

		--If the gun is activated, connect to a function
		mouse.Button1Down:Connect(function()
			if not firing and gun:GetAttribute("PlayedEquipAnimation") then
				firing = true
				while firing == true do
					gunScripts.onActivated()
					wait(firerate)
				end
			end
		end)

		gun.Deactivated:Connect(function()
			firing = false
		end)
		
		UIS.InputBegan:Connect(function(input, GPE)
			if not GPE then
				if input.UserInputType == Enum.UserInputType.Touch then
					if not firing and gun:GetAttribute("PlayedEquipAnimation") then
						firing = true
						while firing == true do
							gunScripts.onActivated()
							wait(firerate)
						end
					end
				end
			end
		end)
		
		UIS.InputEnded:Connect(function(input, GPE)
			if not GPE then
				if input.UserInputType == Enum.UserInputType.Touch then
					firing = false
				end
			end
		end)
		--When the gun is unequipped,
		gun.Unequipped:Connect(function()
			--disable the ammoGUI
			ammoGui.Enabled = false
			--disable the reloadGUI
			ReloadGui.Enabled = false
			--If the animation is still playing after the gun is unequipped,
			if equipAnimTrack.IsPlaying then
				gun:SetAttribute("PlayedEquipAnimation", false)
				--Stop the track
				equipAnimTrack:Stop()
				--Restart the time position.
				equipAnimTrack.TimePosition = 0
			end

			holdAnimTrack:Stop()
			holdAnimTrack.TimePosition = 0
			--Set playedequipanimation to false
			gun:SetAttribute("PlayedEquipAnimation",false)
		end)
	end)
	
	UIS.InputBegan:Connect(function(input, GPE)
		local reloadDebounce = false
		if not GPE then
			if input.KeyCode == Enum.KeyCode.R and ammoAmount < gunIndex.Ammo and reloadDebounce == false and gun:GetAttribute("PlayedEquipAnimation") then
				reloadDebounce = true
				local reloadAnim = GunAnimations:WaitForChild("PistolReload")
				
				local reloadTrack = gunScripts.loadAnimation(animator, char:FindFirstChildWhichIsA("Humanoid"), reloadAnim)
				reloadTrack:Play()
				local reloadSound = gun:WaitForChild("ReloadSound")
				reloadSound:Play()
				
				local isUnequipped = false
				
				gun.Unequipped:Connect(function()
					isUnequipped = true
					if reloadTrack.IsPlaying then
						print("stopped")
						reloadTrack.TimePosition = 0
						reloadTrack:Stop()
						reloadSound:Stop()
						reloadDebounce = false
					end
				end)
				
				reloadTrack.Ended:Connect(function()
					if not isUnequipped then
						print("reloaded")

						ammoAmount = gunIndex.Ammo
						print("ammount = 19")
						ReloadGui.Enabled = false
						reloadDebounce = false
					end
				end)
			end
		end
	end)

end

return gunScripts

As always, thanks for your time.