The Parent property of land is locked, current parent: NULL, new parent Workspace (how to fix?)

local Player = game.Players.LocalPlayer
local Mouse = Player:GetMouse()
local PosX
local PosY 
local PosZ 
local GridSize = 2 
local isplacing = false
local Model = game.ReplicatedStorage.Models.land:Clone()



local function StartPlacement()

    if not isplacing then
    Model.Parent = game.Workspace
      isplacing = true
    end
end



local function Snap()

    PosX = math.floor(Mouse.Hit.X / GridSize + 0.5) * GridSize 
    PosY = Model.PrimaryPart.Position.Y
    PosZ = math.floor(Mouse.Hit.Z / GridSize + 0.5) * GridSize 

end



local function Movement()
if isplacing then

    Mouse.TargetFilter = Model 

    Snap() 

    Model:SetPrimaryPartCFrame(CFrame.new(PosX, PosY, PosZ)) 

end
end




Mouse.KeyDown:connect(function(key)
    if key == "x" and isplacing then
        Model:Destroy()
        isplacing = false

    end
end)



script.Parent.MouseButton1Click:Connect(StartPlacement)
Mouse.Move:connect(Movement)

this is a placement system thing when i got the item and press x works good but when i try to get the item again this message pops up --The Parent property of land is locked, current parent: NULL, new parent Workspace-- and idk why