Why does it throw the error 'not a valid member'?

The following code is a Localsript in ReplicatedFirst.

while wait() do
    if ContentProvider.RequestQueueSize == 0 then
        for i = 0, 1, 0.02 do
            Splashscreen.Background.Logo.ImageTransparency = i
            wait()
        end
        wait(1)
        for i = 0, 1, 0.02 do
            Splashscreen.Background.Transparency = i
            wait()
        end
    end
    Splashscreen:Destroy() -- line 19
end

Why does it throw the error...

14:53:00.748 - Background is not a valid member of ScreenGui 14:53:00.751 - Stack Begin 14:53:00.752 - Script 'ReplicatedFirst.SplashscreenScript', Line 19 14:53:00.752 - Stack End

...even though the Frame Background is a child of the ScreenGui called Splashscreen?