Can't change speed

I can’t seem to be able to change the speed, when I was messing around with Siminov’s weapon settings, the speed was still the same. I also tried using my own LUA, it didn’t work.

I did try to kill myself, switch ironsight on and off and so on, but it seems nothing worked. What could be the problem?

Somehow, for LUA, I think it is because it is outdated;

function playerSetSpeed(ply)
	GAMEMODE:SetPlayerSpeed(ply, 200, 250)
	// 250 is the default move speed
	// 500 is the speed when you hold the sprint key
hook.Add( "PlayerSpawn", "playerSetSpeedtest", playerSetSpeed )