Why my output makes a error: " Workspace.Paragon.Main:65: attempt to index nil with 'Position' "?

Here is the script:

wait()

local player = game.Players
local rp = game:GetService("ReplicatedStorage")

--model

local Model = script.Parent
local Assets = workspace.GameAssets

local beam = Model.Sentry.Beam

-- animations

local Folder = script.Animations
local Idle = Folder.Idle
local Attack = Folder.Attack

local LoadIdle2 = script.Parent.Humanoid:LoadAnimation(Idle)
local LoadAttack = script.Parent.Humanoid:LoadAnimation(Attack)

-- ps

local pS = game:GetService("PhysicsService")

--unidade
local RootPart = Model.PrimaryPart
local Head = Model:WaitForChild("Head")

-- config
local config = Model:WaitForChild("Configuration")
local Dano = config:WaitForChild("Damage")
local Range = config:WaitForChild("Range")
local Cooldown = config:WaitForChild("Cooldown")

-- inimigos

local Enemies = Assets:WaitForChild("Enemies")
local CloseEnemies = {}

local TargetSelected = nil

LoadIdle2:Play()

local function AttackAlvo()

    if CloseEnemies[1] == nil then
        return
    end

    if TargetSelected == nil then

        -- n tem target, ent vai adicionar um novo
        TargetSelected = CloseEnemies[1]

        if TargetSelected ~= nil then
            Model.Shot:Play()
            if TargetSelected and TargetSelected.PrimaryPart then
                coroutine.resume(coroutine.create(function()
                    local att = Instance.new("Attachment")
                    att.Parent = TargetSelected.PrimaryPart
                    beam.Attachment1 = att
                    while TargetSelected do
                        if TargetSelected then
                            local EnemyPos = TargetSelected.PrimaryPart.Position
                            local LookPos = Vector3.new(EnemyPos.X, RootPart.Position.Y, EnemyPos.Z)
                            RootPart.CFrame = CFrame.new(RootPart.Position, LookPos)
                            TargetSelected:FindFirstChild("Humanoid"):TakeDamage(Dano.Value)
                            if TargetSelected:FindFirstChild("Humanoid").Health < 1 then
                                TargetSelected = nil
                                break
                            end
                            wait(Cooldown.Value)
                        end
                    end
                end))
            end
        end

        if TargetSelected ~= nil then
            if TargetSelected:WaitForChild("Humanoid") then

                script.Parent.Shot:Play()
                LoadAttack:Play()
                -- oque o ataque vai fazer aqui

                if TargetSelected.PrimaryPart == nil then
                    return
                else
                    print("ok")
                end


            end
        end


    end

    LoadIdle2:Play()

end




local function ProcurarAlvo()

    CloseEnemies = {}

    for _, Enemy in pairs(Enemies:GetChildren()) do

        if RootPart ~= nil then
            if Enemy.PrimaryPart == nil then
                warn("ratio o bixo n tem primary part")
                return
            end


            local distance = (RootPart.Position - Enemy.PrimaryPart.Position).magnitude

            if (distance < Range.Value) then
                table.insert(CloseEnemies, Enemy)
            end


        else
            warn("po man esqueceu o rootpart no maluco vei")
        end

    end

    AttackAlvo()


end








while true do
    wait(0.1)

    ProcurarAlvo()
end