Animation won't run while walking nor will it play when button is pressed?

local uis = game:GetService("UserInputService")
local player = game.Players.LocalPlayer
local char = player.Character or player.CharacterAdded:Wait()
local smash = Instance.new("Animation")
smash.AnimationId = 'rbxassetid://2941877623'
local usos = char:WaitForChild("Humanoid"):LoadAnimation(smash)
local debounce = false
uis.InputBegan:Connect(function(input)
if input.KeyCode == Enum.KeyCode.E and debounce == false then
char.Humanoid.WalkSpeed = 0
debounce = true
usos:Play()
wait(4)
debounce = false
char.Humanoid.WalkSpeed = 16
end
end)

When I try to run the animation while walking, it starts and then stops immediately, but the walk speed is set to 0. Not only that, but if the animation is playing, and I press a button, the animation stops. Please help.