Why does this error pop up - attempt to index upvalue 'Xpn' (a number value)?

For some reason this error comes up any help? attempt to index upvalue 'Xpn' (a number value)

local plr = game.Players.LocalPlayer

local Xp = plr:WaitForChild("XP") -- Using WaitForChild() so the script won't break if "XP" has not loaded yet.

local lvl = plr:WaitForChild("lvl")

local Xpn = plr:WaitForChild("XpNeeded") -- How much more xp does a person need

  

lvl.Changed:Connect(function()

if lvl.Value == 2 then -- How much Xp needed will get updated

Xpn = Xpn.Value+50

end

end)

  

lvl.Changed:Connect(function()

if lvl.Value == 3 then -- How much Xp needed will get updated

Xpn = Xpn.Value+75

end

end)

  

lvl.Changed:Connect(function()

if lvl.Value == 4 then -- How much Xp needed will get updated

Xpn = Xpn.Value+100

end

end)

  

lvl.Changed:Connect(function()

if lvl.Value == 5 then -- How much Xp needed will get updated

Xpn = Xpn.Value+125

end

end)

  

Xp.Changed:Connect(function()

if Xp.Value >= Xpn.Value then

Xp.Value = Xp.Value-Xpn.Value

lvl.Value = lvl.Value+1

end

end)`