Argument 1 missing or nil on my story game code from Ponchokings ?

I've tried redoing it in a new baseplate but that does not work, the first time I did this it worked but I accidentally deleted the gameScript now it gives Argument 1 missing or nil

  17:16:52.756  Argument 1 missing or nil  -  Server - gameScript:10
  17:16:52.756  Stack Begin  -  Studio
  17:16:52.756  Script 'ServerScriptService.gameScript', Line 10 - function getPlayerImage  -  Studio - gameScript:10
  17:16:52.756  Script 'ServerScriptService.gameScript', Line 78 - function challenge_1  -  Studio - gameScript:78
  17:16:52.756  Script 'ServerScriptService.gameScript', Line 128 - function startGame  -  Studio - gameScript:128
  17:16:52.756  Script 'ServerScriptService.gameScript', Line 136  -  Studio - gameScript:136
  17:16:52.756  Stack End  -  Studio

this is the code that break it

local randomPlayerName
local randomPlayerId

local function getPlayerImage(player_id)
    local content, isReady = game:GetService("Players"):GetUserThumbnailAsync(player_id, Enum.ThumbnailType.HeadShot, Enum.ThumbnailSize.Size420x420)
    return content
end

local function getRandomPlayer()
    local players = game.Players:getPlayers()
    local number = math.random(1,#players)
    local randomPlayer = players[number]
    randomPlayerName = randomPlayer.Name
    randomPlayerId = randomPlayer.UserId
end

idk why it broke it worked the first time but broke at the second time I copied this from Ponchokings Video The link he gave my CreateDialogueEvent:

local player = game.Players.LocalPlayer
local CreateDialogueEvent = game.ReplicatedStorage.CreateDialogueEvent
local DialogueFrame = player.PlayerGui.ScreenGui.Frame

local function playSound(sound_id) -- Plays typing sound
    local sound = Instance.new("Sound",game.ReplicatedStorage)
    sound.SoundId = sound_id
    sound.Volume = .1
    sound.PlayOnRemove = true
    sound:Destroy()
end

local function textAnimate(content) -- Animates each letter
    for i=1,string.len(content) do
        DialogueFrame.TextLabel.Text = string.sub(content,1,i)
        playSound("rbxassetid://915576050")
        if string.sub(content,i,i) == "!" or string.sub(content,i,i) == "." or string.sub(content,i,i) == "?" then
            wait(1)
        elseif  string.sub(content,i,i) == "," then
            wait(.5)
        else
            wait(.05)
        end
    end
end

CreateDialogueEvent.OnClientEvent:Connect(function(image_id, content) -- activates when called from the Server
    if not player:findFirstChild("secretEnding") then
        DialogueFrame.ImageLabel.Image = image_id
        DialogueFrame.TextLabel.Text = ""
        DialogueFrame.Visible = true
        textAnimate(content)
    end
end)

Ponchokings code my gameScript code

local CreateDialogueEvent = game.ReplicatedStorage.CreateDialogueEvent
local TimerEvent = game.ReplicatedStorage.TimerEvent

-- Other Useful Functions

local randomPlayerName
local randomPlayerId

local function getPlayerImage(player_id)
    local content, isReady = game:GetService("Players"):GetUserThumbnailAsync(player_id, Enum.ThumbnailType.HeadShot, Enum.ThumbnailSize.Size420x420)
    return content
end

local function getRandomPlayer()
    local players = game.Players:getPlayers()
    local number = math.random(1,#players)
    local randomPlayer = players[number]
    randomPlayerName = randomPlayer.Name
    randomPlayerId = randomPlayer.UserId
end

----------------------------------------

-- put your challenge functions here
local function move()
    local npc = game.Workspace.Teacher

    local point1 = game.Workspace.Checkpoint1
    local point2 = game.Workspace.Checkpoint2
    local point3 = game.Workspace.Checkpoint3
    local point4 = game.Workspace.Checkpoint4
    local point5 = game.Workspace.Checkpoint5
    local point6 = game.Workspace.Checkpoint6
    local point7 = game.Workspace.Checkpoint7

    npc.Humanoid:MoveTo(point1.Position)
    npc.Humanoid:MoveTo(point2.Position)
    npc.Humanoid:MoveTo(point3.Position)
    npc.Humanoid:MoveTo(point4.Position)
    npc.Humanoid:MoveTo(point5.Position)
    npc.Humanoid:MoveTo(point6.Position)
    npc.Humanoid:MoveTo(point7.Position)
end

local function checkIfPlayerSit()
    for i,v in pairs(game.Players:GetPlayers()) do
        if v.Character then
            if v.Character.Humanoid.Sit ~= true then
                v.Character.Humanoid.Health = 0
            end
        end
    end
end

local function challeng_example() -- THIS IS JUST AN EXAMPLE! IT WON'T RUN
    local teacher_Image = "http://www.roblox.com/asset/?id=8447539851"
    wait(10)
    CreateDialogueEvent:FireAllClients(teacher_Image,"Hello Students!")
    wait(5)
    getRandomPlayer()
    CreateDialogueEvent:FireAllClients(getPlayerImage(randomPlayerId),"I think this is the School!")
end

local function challenge_intro()
    local teacher_Image = 'http://www.roblox.com/asset/?id=8447539851'
    CreateDialogueEvent:FireAllClients(teacher_Image,"Hello Students!")
    wait(2)
    CreateDialogueEvent:FireAllClients(teacher_Image,"Come in the class")
    wait(5)
    CreateDialogueEvent:FireAllClients(teacher_Image,"sit on the chair please")
    TimerEvent:FireAllClients(10)
    wait(10)
    checkIfPlayerSit()
end

local function challenge_1()
    local teacher_Image = 'http://www.roblox.com/asset/?id=8447539851'
    CreateDialogueEvent:FireAllClients(getPlayerImage(randomPlayerId),"I heard there was a ghost here")
    wait(2)
    CreateDialogueEvent:FireAllClients(getPlayerImage(randomPlayerId),"Wait really?")
    wait(2)
    CreateDialogueEvent:FireAllClients(getPlayerImage(randomPlayerId),"It was the ghost of the janitor")
    wait(2)
    CreateDialogueEvent:FireAllClients(getPlayerImage(randomPlayerId),"theres no way thats true")
    wait(2)
    CreateDialogueEvent:FireAllClients(teacher_Image,"Attention class, Theres no such things as ghost")
    wait(2)
    game.Lighting.Ambient = Color3.new(0.176471, 0.176471, 0.176471)
    game.Lighting.TimeOfDay = "1:00:00"
    game.Lighting.Brightness = 3
    game.Lighting.FogEnd = 50
    game.Lighting.FogStart = 10
    CreateDialogueEvent:FireAllClients(getPlayerImage(randomPlayerId),"Huh wheres the light")
    wait(5)
    CreateDialogueEvent:FireAllClients(getPlayerImage(randomPlayerId),"oh no is it the ghost")
    wait(2)
    CreateDialogueEvent:FireAllClients(teacher_Image,"Its probrobly not ill go check it")
    wait(2)
    CreateDialogueEvent:FireAllClients(teacher_Image,"stay here dont go anywhere")
    wait(3)
    move()
    game.Workspace["Huge Scream"]:play()
    wait(2)
    CreateDialogueEvent:FireAllClients(getPlayerImage(randomPlayerId),"What was that")
    wait(2)
end

local function challenge_2()

end

local function challenge_3()

end

local function challenge_4()

end

local function challenge_ending()

end

--------------------------------------------------

local function startGame() -- This is your main function where we order the challenges
    challenge_intro()
    challenge_1()
    challenge_2()
    challenge_3()
    challenge_4()
    challenge_ending()
end

wait(10) -- waits 10 seconds
startGame() -- runs the startGame function

Ponchokings code ask me if you need question cuz this is my first time posting a long question Thanks in Advance