My checkpoints stop working randomly. Do you see any errors in my code?

I used checkpoints that have already been made from the assets, they work most of the time, but sometimes they stop working on a server and when someone dies, it returns them to the initial spawn point. The server will stay in this condition, leading everyone to quit it. I am hoping this is a common problem with an easy fix.

Here is the script in the checkpoints.

local spawn = script.Parent
spawn.Touched:connect(function(hit)
    if hit and hit.Parent and hit.Parent:FindFirstChild("Humanoid") then
        local player = game.Players:GetPlayerFromCharacter(hit.Parent)
        local checkpointData = game.ServerStorage:FindFirstChild("CheckpointData")
        if not checkpointData then
            checkpointData = Instance.new("Model", game.ServerStorage)
            checkpointData.Name = "CheckpointData"
        end

        local checkpoint = checkpointData:FindFirstChild(tostring(player.userId))
        if not checkpoint then
            checkpoint = Instance.new("ObjectValue", checkpointData)
            checkpoint.Name = tostring(player.userId)

            player.CharacterAdded:connect(function(character)
                wait()
                character:WaitForChild("HumanoidRootPart").CFrame = game.ServerStorage.CheckpointData[tostring(player.userId)].Value.CFrame + Vector3.new(0, 4, 0)
            end)
        end

        checkpoint.Value = spawn
    end
end)

Thank you