Script is not increasing a value and doing as it should, with no errors?

I tried making a ranking system, and the script is supposed to increase a value in the player called "xp"

These are the ranks (they might have to do with the error):

local ranks = {
	Student = {
		XPneeded = 0;
		Rank = 1;
	};
	Janitor = {
		XPneeded = 100;
		Rank = 2
	};
	CafeteriaHelper = {
		XPneeded = 150;
		Rank = 3;
	};
	Teacher = {
		XPneeded = 220;
		Rank = 4;
	};
	Nurse = {
		XPneeded = 280;
		Rank = 5;
	};
	Secretary = {
		XPneeded = 350;
		Rank = 6;
	};
	Principal = {
		XPneeded = 500;
		Rank = 7;
	};
}

And this is the rank function (in module script):

function module.giveXPOrRankPlayer(plr,amount)
	-- Pop up
	local gui = game.ReplicatedStorage.UI.GainNotif:Clone()
	gui.Parent = plr.PlayerGui
	gui.TextLabel.Text = "+"..amount.." XP"
	gui.FireTweenAndTrans:FireClient(plr)
	-- Rank and XP stuff
	plr.Value = plr.Value + amount
	print(plr.Name.." has been given "..amount.." XP")
	for i, rank in pairs(ranks) do
		if plr.XP.Value >= rank.XPneeded then
			if ranks[i] == plr.Rank.Value then
				local nextRank = i+1
				plr.Rank = ranks[nextRank]
				
				local converted = tostring(rank)
				print(plr.Name.." has ranked up to "..converted..", "..plr.XP.Value.." XP")
			end
		end
	end
end

Why doesn't the script increase the value/xp?