Problem message dead

Everything works fine except the message from whoever killed you.
when someone kills you, write:
“invalid” killed the name of the dead user.

client.lua

RegisterNetEvent('showNotification')
AddEventHandler('showNotification', function(text)
    ShowNotification(text)
end)
function ShowNotification(text)
    SetNotificationTextEntry("STRING")
    AddTextComponentString(text)
    DrawNotification(0,1)
end
Citizen.CreateThread(function()
    alreadyDead = false
    while true do
        Citizen.Wait(50)
        local playerPed = GetPlayerPed(-1)
        if IsEntityDead(playerPed) and not alreadyDead then
            killer = GetPedKiller(playerPed)
            killername = false
            for id = 0, 64 do
                if killer == GetPlayerPed(id) then
                    killername = GetPlayerName(id)
                end
            end
            if killer == playerPed then
                TriggerServerEvent('playerDied',0,0)
            elseif killername then
                TriggerServerEvent('playerDied',killername,1)
            else
                TriggerServerEvent('playerDied',0,2)
            end
            alreadyDead = true
        end
        if not IsEntityDead(playerPed) then
            alreadyDead = false
        end
    end
end)

server.lua

AddEventHandler('playerConnecting', function()
    TriggerClientEvent('showNotification', -1,"~g~".. GetPlayerName(source).."~w~ se unió.")
end)

AddEventHandler('playerDropped', function()
    TriggerClientEvent('showNotification', -1,"~r~".. GetPlayerName(source).."~w~ se fue.")
end)

RegisterServerEvent('playerDied')
AddEventHandler('playerDied',function(killer,reason)
    if killer == "Invalid" then
        reason = 2
    end
    if reason == 0 then
        TriggerClientEvent('showNotification', -1,"~o~".. GetPlayerName(source).."~w~ se suicidó. ")
    elseif reason == 1 then
        TriggerClientEvent('showNotification', -1,"~o~".. killer .. "~w~ mató a ~o~"..GetPlayerName(source).."~w~.")
    else
        TriggerClientEvent('showNotification', -1,"~o~".. GetPlayerName(source).."~w~ se murió.")
    end
end)

where this error?
thanks

Try this

RegisterNetEvent('showNotification')
AddEventHandler('showNotification', function(text)
	ShowNotification(text)
end)
function ShowNotification(text)
	SetNotificationTextEntry("STRING")
	AddTextComponentString(text)
	DrawNotification(0,1)
end
Citizen.CreateThread(function()
    -- main loop thing
	alreadyDead = false
    while true do
        Citizen.Wait(50)
		local playerPed = GetPlayerPed(-1)
		if IsEntityDead(playerPed) and not alreadyDead then
			killer = GetPedKiller(playerPed)
			killername = false
			for id = 0, 64 do
				if killer == GetPlayerPed(id) then
					killername = GetPlayerName(id)
				end				
			end
		if cfg.deathMessages then
			if killer == playerPed then
				TriggerServerEvent('playerDied',0,0)
			elseif killername then
				TriggerServerEvent('playerDied',killername,1)
			else
				TriggerServerEvent('playerDied',0,2)
			end
		end
			alreadyDead = true
		end
		if not IsEntityDead(playerPed) then
			alreadyDead = false
		end
	end
end)

Now it says nothing, it does not show the message of when they kill you

???¿???