Why is the value not increasing? [Solved]

So I'm making a GUI that when you click it, the number in the GUI will increase by 1

But, the problem is that the number is not increasing at all and it stays at 0

It does print "up" when I click it though

Anything to help?

Extra info:

I'm using a NumberValue

This is also inside a local script

FirstCode = script.Parent.Code1
Code1Num = script.Parent.Code1V

FirstCode.Text = Code1Num.Value

FirstCode.MouseButton1Click:Connect(function()
    print("up")
    Code1Num.Value = Code1Num.Value + 1
end)