Why does my gui not re open once I close it for the first time?

I have a gui that opens when I click on a part and closes when I click a text button. It works fine until I try to re-open that gui again and I'm not sure why that happens.

Here is my code to open the gui:

function onClicked(PlayerWhoClicked)
	    PlayerWhoClicked.PlayerGui.ScreenGui.Frame.Visible = true
	end
	 
	script.Parent.ClickDetector.MouseClick:connect(onClicked)

Here is my code to close the gui:

script.Parent.MouseButton1Click:connect(function()
	script.Parent.Parent.Visible = false
end)

Make sure it was a LOCALSCRIPT.

And make the open the gui script's line 2 like this:

PlayerWhoClicked:WaitForChild("PlayerGui").ScreenGui.Frame.Visible = true

its bc only localscript accepts PlayerGui event, and the PlayerGui is not in the workspace before running the game, so you need to put WaitForChild().