Finding a player returns nil, even though the player exists?

The main issue here is line 25, it always returns as a nil value for the player.

for i = 1, 25 do
	local Sample = script.Sample:Clone()
	Sample.Name = i
	Sample.Parent = script.Parent.SurfaceGui.Frame.ScrollingFrame
	Sample.UserPos.Text = tostring(i)
	Sample.score.Text = "nan-ind"
	Sample.UserName.Text = ""
	Sample.LayoutOrder = i
	script.Parent.SurfaceGui.Frame.ScrollingFrame.CanvasSize = UDim2.new(0,0,0,50*i)
end
function UpdateGui()
	for i,v in pairs(game.Players:GetChildren()) do
		local Data = tonumber(v.leaderstats["High Score"].Value) --score
		local DS = game:GetService("DataStoreService"):GetOrderedDataStore("Score")
		DS:SetAsync(v.UserId,Data)
	end
	local DS = game:GetService("DataStoreService"):GetOrderedDataStore("Score")
	local Pages = DS:GetSortedAsync(false,25)
	local Data = Pages:GetCurrentPage()
	for k,v in pairs(Data) do
		if tonumber(v.key) >=1 then
			local Frame = script.Parent.SurfaceGui.Frame.ScrollingFrame:FindFirstChild(tostring(k))
			if Frame then
				Frame.UserName.Text = game.Players:GetNameFromUserIdAsync(v.key)
				Frame.score.Text = game.Players:FindFirstChild(Frame.UserName.Text).Name
			end
		end
	end
end

while true do
	UpdateGui()
	wait(5)
end

Why is this happening? I've tried to change Frame.UserName.Text to a few others, but they all returned nil as well, yet when I tried my username, it worked perfectly fine. What's happening?