Implementing sprinting in my game, but it wont work?

I have developed a localscript in StarterPlayerScripts and a script in ServerScriptService.

The purpose of these scrips is to add sprinting when the player presses LeftControl.

Here is my code. It is not too many lines so do not worry.

StarterPlayerScripts LocalScript

local uis = game:GetService("UserInputService")

local toggleSprintEvent = game.ReplicatedStorage:WaitForChild("ToggleSprint")

uis.InputBegan:Connect(function(key, processed)
	if processed then return end
	
	if key.KeyCode == Enum.KeyCode.LeftControl then
		
		toggleSprintEvent:FireServer(true)
	end
end)


uis.InputEnded:Connect(function(key, processed)
	if processed then return end
	
	if key.KeyCode == Enum.KeyCode.LeftControl then
		
		toggleSprintEvent:FireServer(false)
		
	end
end)

SeverScriptService Script

local toggleSprintEvent = game.ReplicatedStorage:WaitForChild("ToggleSprint")

toggleSprintEvent.OnServerEvent:Connect(function(player, turnOnSprrint)
	local char = player.Character
	
	if not char:FindFirstChild("Humanoid") then return end
	
	if turnOnSprrint == true then
		char:FindFirstChild("Humanoid").WalkSpeed = 50
		
	else
		char:FindFirstChild("Humanoid").WalkSpeed = 16
	end
end)

Please help!!