[Help] "MSG is not a valid member of Workspace" what?

The code is for a color move game but when I try to run it I got this "MSG is not a valid member of Workspace" but I set MSG to Workspace please help.

---- Locals
local blue = game.Workspace.Model.Blue
local red = game.Workspace.Model.Red
local green = game.Workspace.Model.Green
local yellow = game.Workspace.Model.Yellow

---- Main Code
while true do
	wait(1)
	idkmath = math.random(1, 4)
	if idkmath == 1 then --- bule
		MSG = Instance.new("Message")
		MSG.Parent = game.Workspace
		MSG.Text = ("GO to bule")
		wait(1)
		game.Workspace.MSG:Remove()
		wait(1)
		red.CanCollide = false
		green.CanCollide = false
		yellow.CanCollide = false
	elseif  idkmath == 2 then --- red
		MSG = Instance.new("Message")
		MSG.Parent = game.Workspace
		MSG.Text = ("GO to red")
		wait(1)
		game.Workspace.MSG:Remove()
		wait(1)
		blue.CanCollide = false
		green.CanCollide = false
		yellow.CanCollide = false
	elseif  idkmath == 3 then --- green
		MSG = Instance.new("Message")
		MSG.Parent = game.Workspace
		MSG.Text = ("GO to green")
		wait(1)
		game.Workspace.MSG:Remove()
		wait(1)
		blue.CanCollide = false
		red.CanCollide = false
		yellow.CanCollide = false
	else if idkmath == 4 then
		MSG = Instance.new("Message")
		MSG.Parent = game.Workspace
	    MSG.Text = ("GO to yellow")
		wait(1)
		game.Workspace.MSG:Remove()
		wait(1)
		blue.CanCollide = false
		green.CanCollide = false
		red.CanCollide = false
		end
	end
end