Why does the KeyframeReached event not fire? [UNSOLVED]

I'm trying to make an animation not run a second time until it is finished running the first time. The problem is, however, that the animation only runs once because the KeyframeReached event does not fire. This is a local script in starter gui and nothing appears in the output -- at all.

local plr = game.Players.LocalPlayer
    repeat wait() until plr.Character
local hum = plr.Character:WaitForChild("Humanoid")
local mouse = plr:GetMouse()
local anim = workspace:WaitForChild("Animation")
local canPlay = true

mouse.KeyDown:connect(function(key)
    if key:lower() == "q" and canPlay then
        canPlay = false
        local animTrack = hum:LoadAnimation(anim)

        animTrack.KeyframeReached:connect(function(name)
            print("fired")--Does not print
            print(name)--Does not print
            if name == "End" then
                canPlay = true
            end
        end)

        animTrack:Play()
    end
end)