GetPropertyChangedSignal not receiving update?

Hello,

I'm truly at a loss here. I've written a program that's supposed to convey whatever a StringValue holds onto a TextLabel within the Client's User Interface. To cut back time, I wrote a shortcut function to change the data of the StringValue, which I don't see any present issues in using, or existing in it. However, I could be wrong?

local function SetString(SetInstance, String)
    if not (SetInstance) then
        warn("Unable to Set String for  instance '"..SetInstance.."' (Propterty doesn't exist).")
    return; end
    print("Setting: "..String) -- It relays that the function indeed set it
    SetInstance.Value = String
end
SetString(Container, "Hello, world!") -- Container as StringValue

I have this function run a few times within my Script and it actively sets the String I desire, however when I run that below, it just doesn't upload the information.

Here's the function picking it up.

local ReplicatedStorage = game:GetService("ReplicatedStorage")
local Container = ReplicatedStorage:WaitForChild("Container")
local Player = game:GetService("Players").LocalPlayer
local PlayerGui = Player:WaitForChild("PlayerGui")
local BaseGuis = PlayerGui:WaitForChild("BaseGuis")
local BaseHeader = BaseGuis:WaitForChild("BaseHeader")
local Header = BaseHeader:WaitForChild("Header")
local Header = PlayerGui.BaseGuis.BaseHeader.Header 

Container:GetPropertyChangedSignal("Value"):Connect(function()
    local Currentdata = Container
    Header.Text = Currentdata.Value
end)

If anyone could aid me in the direction of solving this issue that would be greatly appreciated!

Thanks in advance.