won't move part anymore part just floats?? :/

the part is just stuck in the air, it won't fall??

local MainPart = game.Workspace.Part
local TextBox = script.Parent

local function CheckIfCompatible(txt)
	local max = 10
	
	if string.len(txt) >= max then
		return false
	end
	
	if string.len(txt) <= max then
		return true
	end
end

TextBox.FocusLost:Connect(function()
	
	local texts = ""
	
	local text = TextBox.Text
	local Compatible = CheckIfCompatible(text)
	
	if Compatible then
		MainPart.Position = Vector3.new(0, text, 0)
		texts = "Moved Part"
	else
		texts = "Too long to read."
	end
	
	script.Parent.Text = tostring(texts)
end)

Put this into your code:

MainPart.Anchored = false