How do I prevent someone teleporting to a certain area? [REPOST.]

I'm trying to make a teleport script with some areas by which the user can't teleport to. However, at the moment, i'm struggling to get the mouse to detect the area by which is blocked from the user so the user ends up teleporting to it.

Debounce = false
local mouse = script.Parent.Parent:GetMouse()

game:GetService('UserInputService').InputBegan:connect(function(input, gameprossed)
if not gameprossed then

  if input.KeyCode == Enum.KeyCode.T and Debounce == false then
    if mouse.Hit.p == ("No").Position then
      print("No teleport")

    else

      Debounce = true

      local ReplicatedStorage = game:GetService("ReplicatedStorage")
      local Teleport = ReplicatedStorage:WaitForChild("Apparate")

      Teleport:FireServer(mouse.Hit.p)

      wait(2)
      Debounce = false
    end
  end
end
end)

There's no errors in output + no print in the output..

Any ideas on how to overcome it?

Please don't suggest a script which teleports players out of the location if they go in there as it will ruin the aspect of them not being able to enter in the first place.

Thank you.