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?