Playing Sound for one player?

When game runs sound plays normally, but when you click button it doesn't stop

game.Players.PlayerAdded:connect(function(plr)
	
	
			local startsound = plr.PlayerGui:FindFirstChild('Sound')
			
			if startsound then
				if startsound.Name == "BackgroundMusic" then
					startsound:Play()
				end
			end
					
		game.StarterGui.ScreenGui.StartFrame.PlayButton.MouseButton1Click:connect(function()
			local stopsound = plr.PlayerGui:FindFirstChild('Sound')
			
			if stopsound then
				if stopsound.Name == "BackgroundMusic" then
					stopsound:Stop()
				end
			end
		end)
end)