Why is 'Target' a nil value?

game:GetService("RunService").RenderStepped:Connect(function()
    local Target = Mouse.Target or nil
    if Target.Name == "Hitbox" then
        local SelectedItem = Target.Parent
        local TargetUI = script.Parent.Hovering
        if SelectedItem.Information:FindFirstChild("Enabled") and SelectedItem.Parent.Parent.TycoonOwner.Value == Player.Name then
            TargetUI.Visible = false
            TargetUI = script.Parent.HoveringMine
        else
            script.Parent.HoveringMine.Visible = false
        end
        TargetUI.Position = UDim2.new(0, Mouse.X + 20, 0, Mouse.Y + 8)
        TargetUI.ItemName.Text = SelectedItem.Name
        TargetUI.ItemLevel.Text = "Level " .. game.Players[SelectedItem.Parent.Parent.TycoonOwner.Value].SaveStats[SelectedItem.Name].Value
        if TargetUI.Name == "HoveringMine" then
            UpdateToggle(SelectedItem)
        end
        TargetUI.Visible = true
    else
        Mouse.TargetFilter = Target
        script.Parent.HoveringMine.Visible = false
        script.Parent.Hovering.Visible = false
    end
end)

Players.Hexorium.PlayerGui.Interface.ClientHandler:285: attempt to index local 'Target' (a nil value)

^ error

The line in question is line 3 on the code block above. Any reason why this error occurs?