Microsoft Bot Framework: LuisRecognizer Error While Trying to Connect nodeJS with Luis Using Bot Emulator; Cannot Receive Desired Message

I am trying to connect to my Luis app using Bot Emulator.

I have an intent named "Greet" in the Luis app, and am testing it in the Bot Emulator.

The Bot Emulator keeps replying Oops there is something went wrong., after I typed in my training phrase.

For example, "Hi", in the "Greet" intent.

Please tell me what I did was wrong. Thank you very much!

The following pictures are the screenshot of Bot Emulator and the terminal returning an error message.

Bot Emulator showing "Oops, something went wrong and we need to start again after I said "Hello.":

Cache gave an error message at request._callback and self._callback:

The following is my NodeJS code (I had my LuisAPIKey and LuisAppId in my code locally, here I deleted them):

var restify = require('restify');
var builder = require('botbuilder');
var server = restify.createServer();

server.listen(process.env.port || process.env.PORT || 3987, function () {
     console.log('%s listening to %s', server.name, server.url); 
});
var connector = new builder.ChatConnector();

server.post('/api/messages', connector.listen());

var bot = new builder.UniversalBot(connector);

var luisAppId = '';
var luisAPIKey = '';
var luisAPIHostName = 'https://westus.api.cognitive.microsoft.com';

const luisModelUrl = 'https://' + luisAPIHostName + '/luis/v2.0/apps' + luisAppId + '?subscription-key=' + luisAPIKey;

var recognizer = new builder.LuisRecognizer(luisModelUrl);
var intents = new builder.IntentDialog({
    recognizers: [recognizer]
})

bot.dialog('/', intents);

intents.matches('Greet', (session) =>{
    session.send("Hello there! How can I help you today?");
})
.onDefault((session, args, next) => {
    console.log(args);
    session.send("Sorry, I did not understand.");
})