Unable to cast value to object. Why?

This issue is happening on the server script of a function that displays a message to another user, which therefore requires filtering. However when it gets to this line it throws out the error:

Unable to cast value to Object, Line 9

Script:

local onRecievingWarning = game.ReplicatedStorage.FilterWarning


onRecievingWarning.OnServerEvent:connect(function(player, message, victim)
    print("Triggered!")
    player = victim
    print(player)  --Used to make sure the I didn't mess up the order on the client side
    local filteredText = game:GetService("Chat"):FilterStringForBroadcast(player, message)
    local warngooey = game.ReplicatedStorage:WaitForChild("TPSWarnGUI"):Clone()
    warngooey.Enabled = true
    warngooey.LoginForm.Rsn.Text = filteredText
    warngooey.Parent = game.Players[player].PlayerGui
    wait(3)
    game.Players[player].PlayerGui.TPSWarnGUI:Destroy()
end)