Roblox Studio error

FireClient: player argument must be a Player object

What FireClient: player argument must be a Player object means in Roblox Studio, the three things that cause it with the code that triggers each, and the fix for each one.

Updated 5 November 20264 min readErrorLuauWritten by

In short

remote:FireClient(player, ...) sends a message to one player, so its first argument must be that player's Player object, the one in the Players service. Anything else in that slot stops the script with this error: a character Model, a part, a name, a UserId, or the data you meant to send. Everything after the player is the data, and it can be anything a remote can carry.

  • From a Touched event, turn the character into a player with Players:GetPlayerFromCharacter(hit.Parent) first, and skip the hit when it returns nil.
  • From a name or a UserId, use Players:FindFirstChild(name) or Players:GetPlayerByUserId(id).
  • To send to everyone, use FireAllClients(...), which takes no player.
On this page
  1. What it means
  2. Causes and fixes
  3. Fix it with RoCode
  4. Find the line
  5. Questions
  6. Sources

What the message means

Output (example)
ServerScriptService.CoinPads:14: FireClient: player argument must be a Player object

Other forms of the same message:

  • InvokeClient: player argument must be a Player object

The server talks to one client at a time, and Roblox needs to know which connection to send on. Only a Player identifies that connection, so the check happens before anything is sent: nothing reaches any client when this error fires.

The same rule applies to RemoteFunction:InvokeClient(player, ...), which prints InvokeClient: player argument must be a Player object. On the client side there is no player argument at all: FireServer(...) sends only data, and the server receives the sender as the first argument of OnServerEvent automatically.

Causes and fixes

Three things cause this error in practice. Each one below has the smallest code that triggers it, then the fix.

The character from Touched was passed instead of the player

Touched gives you the part that touched, and hit.Parent is the character Model. A Model is not a Player, even though it has the player's name.

Breaks Script in ServerScriptService named CoinPads
local ReplicatedStorage = game:GetService("ReplicatedStorage")

local showCoins = ReplicatedStorage:WaitForChild("ShowCoins") :: RemoteEvent
local pad = workspace:WaitForChild("CoinPad") :: BasePart

pad.Touched:Connect(function(hit: BasePart)
	local character = hit.Parent
	-- a character Model: FireClient: player argument must be a Player object
	showCoins:FireClient(character :: any, 10)
end)

Look the player up from the character, and ignore touches that are not from a player (a loose part, an NPC).

Fixed Script in ServerScriptService named CoinPads
local Players = game:GetService("Players")
local ReplicatedStorage = game:GetService("ReplicatedStorage")

local showCoins = ReplicatedStorage:WaitForChild("ShowCoins") :: RemoteEvent
local pad = workspace:WaitForChild("CoinPad") :: BasePart

pad.Touched:Connect(function(hit: BasePart)
	local character = hit.Parent
	local player = if character and character:IsA("Model") then Players:GetPlayerFromCharacter(character) else nil
	if player then
		showCoins:FireClient(player, 10)
	end
end)

Touched fires many times for one step onto a pad. Add a cooldown per player before giving anything: the debounce guide shows how.

A name, a UserId or a player list was passed

Saved data, chat commands and leaderboards often hold a player's Name or UserId. Those are a string and a number. A table of players, such as the result of Players:GetPlayers(), is not one Player either.

Breaks Script in ServerScriptService named Rounds
local ReplicatedStorage = game:GetService("ReplicatedStorage")

local notify = ReplicatedStorage:WaitForChild("Notify") :: RemoteEvent

local function tellWinner(winnerName: string)
	-- a string: FireClient: player argument must be a Player object
	notify:FireClient(winnerName :: any, "You won the round!")
end

tellWinner("Builderman")

Find the Player object from the name or the UserId, and check that the player is still in the server. For a list, fire once per player in a loop, or use FireAllClients.

Fixed Script in ServerScriptService named Rounds
local Players = game:GetService("Players")
local ReplicatedStorage = game:GetService("ReplicatedStorage")

local notify = ReplicatedStorage:WaitForChild("Notify") :: RemoteEvent

local function tellWinner(winnerUserId: number)
	local player = Players:GetPlayerByUserId(winnerUserId)
	if player then -- nil if they left before the round ended
		notify:FireClient(player, "You won the round!")
	end
end

tellWinner(156)

The player was left out, so the data went first

Code moved from a LocalScript often keeps the client form, FireServer(data), with the word changed to FireClient(data). Then the data sits where the player should be.

Breaks Script in ServerScriptService named Hud
local Players = game:GetService("Players")
local ReplicatedStorage = game:GetService("ReplicatedStorage")

local updateHud = ReplicatedStorage:WaitForChild("UpdateHud") :: RemoteEvent

Players.PlayerAdded:Connect(function(player: Player)
	print(player.Name, "joined")
	-- the table is first: FireClient: player argument must be a Player object
	updateHud:FireClient({ coins = 0, level = 1 } :: any)
end)

Put the player first, then the data. The LocalScript's OnClientEvent receives only the data, without the player.

Fixed Script in ServerScriptService named Hud
local Players = game:GetService("Players")
local ReplicatedStorage = game:GetService("ReplicatedStorage")

local updateHud = ReplicatedStorage:WaitForChild("UpdateHud") :: RemoteEvent

Players.PlayerAdded:Connect(function(player: Player)
	updateHud:FireClient(player, { coins = 0, level = 1 })
end)

A client that has only just joined may not have connected its OnClientEvent yet. Roblox queues remote events that arrive before a listener exists, but for state such as coins it is simpler to keep the value in leaderstats or an attribute, which replicate on their own.

Fix it in your place

Paste the error, RoCode fixes it in your place

Copy the line from Output and paste it here. RoCode opens the script it names in the place you have open in Studio, works out which of the causes above it is, and edits the code there instead of handing you a snippet to paste.

For example: ServerScriptService.CoinPads:14: FireClient: player argument must be a Player object

RoCode is an AI agent for Roblox Studio: it reads the scripts in the place you have open, finds the line and edits it there, and every change is an undo point. It runs on Windows or macOS with a desktop browser. Free to start, with free credits every day.

How to find the line that causes it

  1. Click the red line in Output to open the script at the FireClient call.
  2. Above the call, add print(typeof(x), x) for the value you pass first, and press Play. A Player prints Instance and its name, so also try print(x:IsA("Player")) when it is an Instance.
  3. Follow that value back to where it came from: a Touched handler, a saved name, a loop over a table.

Questions

What should the first argument of FireClient be?

The Player object of the player you are sending to, as found in the Players service. Everything after it is the data.

How do I get the Player from a character?

Use Players:GetPlayerFromCharacter(character). It returns nil for NPCs and anything that is not a player's character, so check the result before you use it.

How do I send a remote event to every player?

Call remote:FireAllClients(...) on the server. It takes only the data. To skip one player, loop over Players:GetPlayers() and call FireClient for each one you want.

Does FireServer need the player too?

No. A LocalScript calls FireServer(data), and Roblox adds the sender as the first argument of OnServerEvent on the server. Passing the player yourself just adds it again as data.

Can RoCode fix it?

Yes. Paste the Output line into RoCode. It reads the script in your open place, finds where the value came from and passes the right Player.

Sources and further reading

How the code was checked: every block marked Fixed passes Luau's strict type checker against Roblox's API definitions (luau-lsp, 5 November 2026), and every block marked Breaks compiles and fails only when it runs. The message wording was checked against the message strings in Roblox Studio itself (macOS build installed 2 November 2026) and the RemoteEvent:FireClient reference on 5 November 2026. A type check catches misspelt APIs and wrong types, not game logic, so playtest in Studio before you publish.

ErrorFireServer can only be called from the clientA RemoteEvent was used from the wrong side: FireServer or OnClientEvent in a server Script, FireClient or OnServerEvent in a LocalScript.ErrorUnable to cast value to ObjectA Roblox function wanted an Instance (a Player, a Part) and got a number, a string, a table or a CFrame instead.WarningRemote event invocation queue exhaustedA RemoteEvent was fired many times with no handler on the other side, so Roblox stored them until the queue filled, then dropped them.TutorialRemoteEvents and RemoteFunctionsClient to server and back, with the checks the server needs.TutorialDebounce and cooldownsStop Touched firing ten times, add cooldowns per player and rate-limit remotes.

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