NPC Dont reply

[VictorSkyer1]

This is a free code that I found somewhere. The NPC stops responding every so often and some people do not respond, there are no errors in the console.

<?xml version="1.0" encoding="UTF-8"?>
<npc name="Veradin" script="veradin.lua" walkinterval="2000" floorchange="0">
    <health now="100" max="100" />
    <look type="472" head="97" body="104" legs="115" feet="38" addons="3" mount="427" />
</npc>

local keywordHandler = KeywordHandler:new()
local npcHandler = NpcHandler:new(keywordHandler)
NpcSystem.parseParameters(npcHandler)

function onCreatureAppear(cid)              npcHandler:onCreatureAppear(cid)            end
function onCreatureDisappear(cid)           npcHandler:onCreatureDisappear(cid)         end
function onCreatureSay(cid, type, msg)      npcHandler:onCreatureSay(cid, type, msg)    end
function onThink()                          npcHandler:onThink()                        end

function creatureSayCallback(cid, type, msg)
    local player = Player(cid)
    local mounts =
    {
        ["azudocus"] = {tokens = 775, mountId = 44},
        ["carpacosaurus"] = {tokens = 775, mountId = 45},
        ["platesaurian"] = {tokens = 775, mountId = 37},
        ["armoured war horse"] = {tokens = 425, mountId = 23},
        ["shadow draptor"] = {tokens = 425, mountId = 24},
        ["crimson ray"] = {tokens = 525, mountId = 33},
        ["steelbeak"] = {tokens = 525, mountId = 34},
        ["dragonling"] = {tokens = 775, mountId = 31},
        ["crystal wolf"] = {tokens = 425, mountId = 16},
        ["black sheep"] = {tokens = 425, mountId = 4},
        ["donkey"] = {tokens = 425, mountId = 13},
        ["midnight panther"] = {tokens = 525, mountId = 5},
        ["rapid boar"] = {tokens = 525, mountId = 10},
        ["uniwheel"] = {tokens = 775, mountId = 15},
        ["vortexion"] = {tokens = 800, mountId = 99},

    }
    
    local outfits =
    {
        ["entrepreneur"] = {tokens = 775, outfitMale = 472, outfitFemale = 471},
        ["recruiter"] = {tokens = 525, outfitMale = 746, outfitFemale = 745},
        ["jersey"] = {tokens = 425, outfitMale = 619, outfitFemale = 620},
    }
    
    mounts[msg] = mounts[msg:lower()]
    outfits[msg] = outfits[msg:lower()]

    if(not npcHandler:isFocused(cid)) then
        return false
    end
    
    if msgcontains(msg, 'balance') then
       npcHandler:say("You have {"..player:getTokens().." Crown Tokens}.", cid)
        return true
    end

    if msgcontains(msg, 'mounts') then
        npcHandler:say("Mounts available at the moment {Azudocus}, {Carpacosaurus}, {Platesaurian}, {Armoured War Horse}, {Crimson Ray}, {Dragonling}, {Crystal Wolf}, {Black Sheep}, {Donkey}, {Midnight Panther}, {Rapid Boar}, {Uniwheel}, {Vortexion}, and {Steelbeak}.", cid)
    elseif msgcontains(msg, 'outfits') then
        npcHandler:say("Outfits available at the moment {Entrepreneur}, {Recruiter} and {Jersey}.", cid)
    elseif not mounts[msg] and not outfits[msg] then
        npcHandler:say("Sorry, choose another option as a reward.", cid)
        return true
    end
    
    if mounts[msg] then
        if player:hasMount(mounts[msg].mountId) then
            npcHandler:say("You already own this mount.", cid)
            return true
        end
        if player:getTokens() >= mounts[msg].tokens then
            npcHandler:say("You were rewarded with the mount {"..msg.."} for "..mounts[msg].tokens.." Crown Tokens", cid)
            player:removeTokens(mounts[msg].tokens)
            player:addMount(mounts[msg].mountId)
            player:getPosition():sendMagicEffect(CONST_ME_MAGIC_BLUE)
        else
            npcHandler:say("You need to {"..mounts[msg].tokens.." Crown Tokens} to receive this mount.", cid)
        end
    elseif outfits[msg] then
        if player:hasOutfit(outfits[msg].outfitMale, 3) or player:hasOutfit(outfits[msg].outfitFemale, 3) then
            npcHandler:say("You already own this outfit.", cid)
            return true
        end
        if player:getTokens() >= outfits[msg].tokens then
            npcHandler:say("You were rewarded with the outfit {"..msg.."} for complete "..outfits[msg].tokens.." Crown Tokens", cid)
            player:removeTokens(outfits[msg].tokens)
            player:addOutfitAddon(outfits[msg].outfitMale, 3)
            player:addOutfitAddon(outfits[msg].outfitFemale, 3)
            player:getPosition():sendMagicEffect(CONST_ME_MAGIC_BLUE)
        else
            npcHandler:say("You need to {"..outfits[msg].tokens.." Crown Tokens} to receive this Outfit.", cid)
        end
    end
    return true
end

keywordHandler:addKeyword({'crown tokens'}, StdModule.say, {npcHandler = npcHandler, text = "Crown Tokens are a kind of tokens that you can exchange for rewards, with each level you pick up counting from the 20 you will automatically receive 5 Crown Tokens, to check how many you already have, say {balance} or {trade} to exchange for some reward."})
keywordHandler:addKeyword({'trade'}, StdModule.say, {npcHandler = npcHandler, text = "To exchange and receive your reward choose what you want: {outfits} or {mounts}."})

npcHandler:setMessage(MESSAGE_GREET, "Welcome |PLAYERNAME|. I can offer rewards in exchange for {Crown Tokens}.")
npcHandler:setMessage(MESSAGE_WALKAWAY, "Good bye!")
npcHandler:setMessage(MESSAGE_FAREWELL, "Good bye and enjoy your stay in Thoria, |PLAYERNAME|.")

npcHandler:setCallback(CALLBACK_GREET, greetCallback)
npcHandler:setCallback(CALLBACK_MESSAGE_DEFAULT, creatureSayCallback)
npcHandler:setCallback(CALLBACK_ONRELEASEFOCUS, onReleaseFocus)
npcHandler:addModule(FocusModule:new())