Why won't this attachment parent to the character?

I am trying to make it so that the player could equip a halo, but every time I try to equip a halo I get the error: "Parent cannot be assigned to" I don't know what could be causing the issue. Here is the server script:

local function equipHalo(plr,color)
	if plr.HaloInventory:FindFirstChild(color.."Halo") == nil then return "halo" end
	if plr.HaloInventory:FindFirstChild(color.."Halo") then
		local clone = game.ReplicatedStorage.Halos[color.."Halo"]:Clone()
		local char = plr.Character
		
		if clone ~= nil and char ~= nil then
			if char:FindFirstChild(plr.Name.."'s Halo") then char[plr.Name.."'s Halo"]:Destroy() end
			clone.Name = plr.Name.."'s Halo"
			clone.CFrame = char.Head.CFrame
			local size = clone.Size
			
			local attatchmentchar = Instance.new("Attachment")
			attatchmentchar.Visible = false
			attatchmentchar = Vector3.new(0,2.5,0) + size
			attatchmentchar.Parent = char:WaitForChild("HumanoidRootPart")
			
			local attatchmenthalo = Instance.new("Attachment")
			attatchmenthalo.Visible = false
			attatchmenthalo.Parent = clone
			
			local alignposition = Instance.new("AlignPosition")
			alignposition.MaxForce = 25000
			alignposition.Attachment0 = attatchmenthalo
			alignposition.Attachment1 = attatchmentchar
			alignposition.Responsiveness = 200
			alignposition.Parent = clone
			
			local alignorientation = Instance.new("AlignOrientation")
			alignorientation.MaxTorque = 25000
			alignorientation.Attachment0 = attatchmenthalo
			alignorientation.Attachment1 = attatchmentchar
			alignorientation.Responsiveness = 200
			alignorientation.Parent = clone
			
			clone.Parent = char
			return "yes"
		end
	end
end

game.ReplicatedStorage.Remotes.EquipHalo.OnServerInvoke = equipHalo

I mean you can make it as an accessory its way easier. But about your script I think its the Halo because I think the Halo is a model which can't be parented with an Attachment it should be a Basepart. But I recommend making it as an accessory and cloning it to the character.

I just realized on line 15:

attatchmentchar = Vector3.new(0,2.5,0) + size

I was setting the Instance instead of the position. Thanks for your effort!