Infinite yield possible - bug. How to fix?

It works in studio, but outside studio it does not work. The error is on line 20

I get this error in Server Log:

Infinite yield possible on 'Players.Nanaluk01.PlayerGuiWaitforChild("ChatGui")' Script 'ServerScriptService.Chat', Line 20

How can I fix this?

Here Is The Coding:

Please Note: -The Error Lies On Line 20 -The .Fr you can see is Frame. I don't know why it disappears in this question.

function UpdateOldLabels(Parent)
    for i,v in pairs(Parent:GetChildren()) do
        if v.Name:sub(1,4):lower() == "line" then
            local LineNumber = v.Name:sub(5)
            if LineNumber == "7" then
                v:Destroy()
            else
                v.Name = "line"..tostring(tonumber(LineNumber) + 1)
                v.Position = v.Position - UDim2.new(0,0,0,15)
            end
        end
    end
end

game.Players.PlayerAdded:connect(function(player)
	for _,v in ipairs(game:GetService("Players"):GetChildren()) do
		wait(1)
		UpdateOldLabels(v:WaitForChild("PlayerGui"):WaitForChild("ChatGui").Frame)
		if player then
			newchatline = Instance.new("TextLabel",v:WaitForChild("PlayerGui").ChatGui.Frame)
			newchatline.Text = "[Server] "..player.Name.. " Has Joined The Server!"
			newchatline.Size = UDim2.new(1,0,0,20)
			newchatline.Position = UDim2.new(0,0,1,-15)
			newchatline.Font = "ArialBold"
			newchatline.TextStrokeTransparency = 1
			newchatline.BackgroundTransparency = 1
			newchatline.BorderSizePixel = 0
			newchatline.FontSize = "Size18"
			newchatline.TextXAlignment = "Left"
			newchatline.TextYAlignment = "Top"
			newchatline.ClipsDescendants = true
			newchatline.Name = "line1"
			newchatline.TextColor3 = Color3.new(1,1,1)
		end
	end 
	UpdateOldLabels(game:GetService("StarterGui").ChatGui.Frame)
	newchatline:Clone().Parent = game:GetService("StarterGui").ChatGui.Frame
	player.Chatted:connect(function(msg)
		for _,v in ipairs(game:GetService("Players"):GetChildren()) do
			UpdateOldLabels(v:WaitForChild("PlayerGui").ChatGui.Frame)
			newchatline = Instance.new("TextLabel",v:WaitForChild("PlayerGui").ChatGui.Frame)
			newchatline.Text = player.Name..": "..msg
			newchatline.Size = UDim2.new(1,0,0,20)
			newchatline.Position = UDim2.new(0,0,1,-15)
			newchatline.Font = "ArialBold"
			newchatline.TextStrokeTransparency = 1
			newchatline.BackgroundTransparency = 1
			newchatline.BorderSizePixel = 0
			newchatline.FontSize = "Size18"
			newchatline.TextXAlignment = "Left"
			newchatline.TextYAlignment = "Top"
			newchatline.ClipsDescendants = true
			newchatline.Name = "line1"
			newchatline.TextColor3 = Color3.new(1,1,1)
		end
		UpdateOldLabels(game:GetService("StarterGui").ChatGui.Frame)
		newchatline:Clone().Parent = game:GetService("StarterGui").ChatGui.Frame
	end)
end)

i get this weird error how do i gonna fix it hapend on a crash

19:32:18.826 - Infinite yield possible on 'Workspace.crazygamespp:WaitForChild("Right Arm")' 19:32:18.826 - Stack Begin 19:32:18.829 - Script 'ServerScriptService.CombatHandler', Line 16 19:32:18.829 - Stack End

picture here https://i.imgur.com/3G2zFq3.png