ESOUI - First addon, not sure why it doesn't work (chat alert sounds)

I know that this is bare minimum functionality at the moment, just trying to see if I can create something simple at first. The goal is to play a sound when a friend says something in chat.

You'll see I have a message in the chat window, just for testing purposes. The test message works, but the sound doesn't play (and I've tried different sounds). What am I conceptually missing?

Code:

ChatAlert = {}



function ChatAlert.init(eventCode, addOnName)

    if addOnName ~= "ChatAlert" then

        return

    end

    d("ChatAlert loaded")

    ZO_ChatSystem_AddEventHandler(EVENT_CHAT_MESSAGE_CHANNEL, ChatAlert.handleChat)

end



function ChatAlert.handleChat(messageType, fromName, text)

    if IsFriend(fromName) then

        PlaySound(SOUNDS.VOLUME_DING_VO)

        d("Messag received")

    end

end



EVENT_MANAGER:RegisterForEvent("ChatAlert", EVENT_ADD_ON_LOADED, ChatAlert.init)

Edit: nevermind, figured it out. VOLUME_DING_VO apparently is not actually an audible sound...