Im trying to make a code script that fires to the server, but i cant get it to work?

So i always get attempt to index nil 'whatever' and im using remote functions, this is when i fire the server

local player = game.Players.LocalPlayer
local textbox = script.Parent.Parent.TextBox
local button = script.Parent
script.Parent.MouseButton1Click:Connect(function(player)
game.ReplicatedStorage.CodeRedeem:FireServer(player, textbox, button)
end

)

and this script is when the server is fired

game.ReplicatedStorage.CodeRedeem.OnServerEvent:Connect(function(player, textbox, button)

        local reward = 9000
    if textbox.Text == "E" --Insert Codes here
        then
            print("Right Code")
            button.Text = 'Redeemed!'
            textbox.LocalScript.ching:Play()
            wait(1)
            textbox.Text = "[INSERT CODE HERE]"
            game.Players.LocalPlayer.leaderstats.Cash.Value = game.Players.LocalPlayer.leaderstats.Cash.Value + reward
    else
        print("Wrong Code")
                button.Text = "Invalid Code"
                textbox.LocalScript.error:Play()
                wait(1)
                textbox.Text = "[INSERT CODE HERE]"
        end
end)