How to filter custom chat?

It's supposed to filter chat

local ChatService = game:GetService("Chat")
 
local chatMessage = game.ReplicatedStorage.ChatMessage
 

local function onChatReceived(sender, message)

	for _, player in pairs(game.Players:GetPlayers()) do
		if sender ~= player then
			local filteredMessage
			if game:GetService("RunService"):IsStudio() then
			
				chatMessage:FireClient(player, sender, message)
			else
				local success, filteredMessage = pcall(function() return ChatService:FilterStringForBroadcast(filteredMessage, sender, player) end)
				if not success then
					filteredMessage = "<Failed to filter message>"
				end
				chatMessage:FireClient(player, sender, filteredMessage)
			end
		end
		end
end
 

chatMessage.OnServerEvent:connect(onChatReceived)

-- ROBLOX Services
local ContextActionService = game:GetService("ContextActionService")
 
-- Static variables
local MAX_MESSAGES = 10
local MESSAGE_HEIGHT = 25
 local NUM_MESSAGE = 0

-- Local variables
local player = game.Players.LocalPlayer
local messages = {}
local chatMessageEvent = game.ReplicatedStorage.ChatMessage
 
-- Variables for GUI elements
local chatScreen = script.Parent
local chatFrame = chatScreen:WaitForChild("ChatFrame")
local chatInput = chatFrame.ChatInput
local messageFrame = chatFrame.MessageFrame
-- Make a copy of the message that will be used later
local messageTemplate = messageFrame.Message:Clone()
messageFrame.Message:Destroy()
 
 
local function addMessage(sender, message)
	-- Check if the number of messages has hit the maximum
	--if #messages >= MAX_MESSAGES then
		-- If so remove the oldest message from the table
	--	table.remove(messages, #messages):Destroy()
	--end
 
	-- Shift all of the messages up one slot

	-- Create new message GUI elements and add to the message table
	if messageFrame:FindFirstChild("LastMessage") then
		messageFrame.LastMessage.Name = "Message"
	end
	local newMessage = messageTemplate:Clone()
	newMessage.NameLabel.Text = sender.Name .. ": "
	newMessage.Content.Text = message
	newMessage.Name = "LastMessage"
	newMessage.Parent = messageFrame
	newMessage.Position = UDim2.new(1, 0, 0, NUM_MESSAGE*MESSAGE_HEIGHT)
	newMessage:TweenPosition(UDim2.new(0, 0, 0, NUM_MESSAGE*MESSAGE_HEIGHT), "Out", "Quad", 0.4,false)
	if newMessage.Position.Y.Offset ==  200 then
	messageFrame.CanvasSize = messageFrame.CanvasSize + UDim2.new(0, 0, 0, 25)
	messageFrame.CanvasPosition = messageFrame.CanvasPosition + Vector2.new(0, 25)
	elseif newMessage.Position.Y.Offset > messageFrame.eh.Position.Y.Offset then
		messageFrame.CanvasSize = messageFrame.CanvasSize + UDim2.new(0, 0, 0, 25) 
		messageFrame.CanvasPosition = messageFrame.CanvasPosition + Vector2.new(0, 25)
	end
	table.insert(messages, 1, newMessage)
	NUM_MESSAGE = NUM_MESSAGE + 1
end
 
-- Function when the input TextBox looses focus
local function onFocusLost(enterPressed, inputObject)
	-- Check if TextBox lost focus because the user pressed "Enter"
	if enterPressed then
		if chatInput.Text ~= "" then
		-- Add the message to the GUI (no need to filter messages from the local player)
		addMessage(player, chatInput.Text)
		-- Send message to the server to get filtered and sent to other players
		chatMessageEvent:FireServer(chatInput.Text)
		-- Reset TextBox text
		chatInput.Text = "Press '/' or click here to chat"
		if game.Players.LocalPlayer:FindFirstChild("Chatting") then
			game.Players.LocalPlayer.Chatting:Destroy()
		end
		else
			chatInput.Text = "Press '/' or click here to chat"
		if game.Players.LocalPlayer:FindFirstChild("Chatting") then
			game.Players.LocalPlayer.Chatting:Destroy()
		end
		end
	elseif  inputObject.UserInputType == Enum.UserInputType.MouseButton1 then
		chatInput.Text = "Press '/' or click here to chat"
		if game.Players.LocalPlayer:FindFirstChild("Chatting") then
			game.Players.LocalPlayer.Chatting:Destroy()
		end
	end
end
 
-- Function when the player presses the slash key
local function onSlashPressed(actionName, inputState, inputObject)
	if inputState == Enum.UserInputState.End then
		-- If key up then capture focus in the TextBox so the user can start typing
		if game.Players.LocalPlayer:FindFirstChild("Chatting") then
			game.Players.LocalPlayer.Chatting:Destroy()
		end
		local Prev = Instance.new("StringValue",game.Players.LocalPlayer)
		Prev.Name = "Chatting"
		chatInput:CaptureFocus()
	end
end
 
-- Disable ROBLOX default chat
game.StarterGui:SetCoreGuiEnabled(Enum.CoreGuiType.Chat, false)

 script.Parent.ChatFrame.MessageFrame.AutoSizeCanvas = true

-- Bind functions
chatMessageEvent.OnClientEvent:connect(addMessage)
chatInput.FocusLost:connect(onFocusLost)
ContextActionService:BindAction("Chatting", onSlashPressed, false, Enum.KeyCode.Slash)

First off it's FilterStringAsync, FilterStringForBroadcast would only be for the message and the sender, not the all server (Player), and FilterStringAsync was made for chat second, It's if not game:GetService("RunService"):IsStudio() then (Publish it) and try it in Play Mode.