https://www.udemy.com/course/comprehensive-alexa-skill-development-course/learn/lecture/6680210#questions/7303418 I had to update the JavaScript and the JSON provided in the Udemy course that has not been updated.

event.json

{
    "session":{
      "new": true,
      "sessionId":"SessionId.[unique-value-here]",
      "application":{
        "applicationId":"amzn1.ask.skill.[YOUR_SKILL_ID_HERE]"
      },
      "attributes":{
        "key": "string value"
      },
      "user":{
        "userId":"amzn1.ask.account.[unique-value-here]"
      }
    },
    "request": {
      "intent": {
        "slots": {
          "FirstName": {
            "name": "FirstName",
            "value": "John"
          }
        },
        "name": "HelloIntent"
      },
      "type": "IntentRequest",
      "requestId": "request5678"
    },
    "context":{
      "System":{
        "application":{
          "applicationId":"amzn1.ask.skill.[YOUR_SKILL_ID_HERE]"
        },
        "user":{
          "userId":"amzn1.ask.account.[unique-value-here]"
        },
        "device":{
          "supportedInterfaces":{
          }
        }
      }
    },
    "version":"1.0"
  }

index.js

"use strict"

const Alexa = require('ask-sdk-core');

const TITLE_CARD = 'Greetings Jeeves'

const getWish = function getWish() {
    const myDate = new Date()
    let hours = myDate.getUTCHours() - 5
    if (hours < 0) {
        hours = hours + 24
    }

    if (hours < 12) {
        return "Good morning."
    } else if (hours < 18) {
        return "Good afternoon."
    } else {
        return "Good evening."
    }
}

const LaunchRequestHandler = {
    canHandle(handlerInput) {
        return handlerInput.requestEnvelope.request.type === 'LaunchRequest';
    },
    handle(handlerInput) {
        const speechText = "Welcome to Greetings Jeeves. Using our skill you can greet your guests. Whom do you want to greet?";
        const repromptText = "You can say, for example, say hello to John."

       return handlerInput.responseBuilder
            .speak(speechText)
            .reprompt(repromptText)
            .withSimpleCard(TITLE_CARD, speechText)
            .getResponse();
    }
}

const CancelAndStopIntentHandler = {
    canHandle(handlerInput) {
        return handlerInput.requestEnvelope.request.type === 'IntentRequest'
            && (handlerInput.requestEnvelope.request.intent.name === 'AMAZON.CancelIntent'
            || handlerInput.requestEnvelope.request.intent.name === 'AMAZON.StopIntent');
    },
    handle(handlerInput) {
        const speechText = 'Goodbye!';

        return handlerInput.responseBuilder
            .speak(speechText)
            .withSimpleCard(TITLE_CARD, speechText)
            .withShouldEndSession(true)
            .getResponse();
    }
};

const ErrorHandler = {
    canHandle() {
        return true;
    },
    handle(handlerInput, error) {
        console.log(`Error handled: ${error.message}`);

        return handlerInput.responseBuilder
            .speak('Sorry, I can\'t understand the command. Please say again.')
            .reprompt('Sorry, I can\'t understand the command. Please say again.')
            .getResponse();
    },
}

const HelpIntentHandler = {
    canHandle(handlerInput) {
      return handlerInput.requestEnvelope.request.type === 'IntentRequest'
        && handlerInput.requestEnvelope.request.intent.name === 'AMAZON.HelpIntent';
    },
    handle(handlerInput) {
      const speechText = 'You can say hello to me!';

      return handlerInput.responseBuilder
        .speak(speechText)
        .reprompt(speechText)
        .withSimpleCard(TITLE_CARD, speechText)
        .getResponse();
    }
}

const SessionEndedRequestHandler = {
    canHandle(handlerInput) {
        return handlerInput.requestEnvelope.request.type === 'SessionEndedRequest';
    },
    handle(handlerInput) {
        //any cleanup logic goes here
        return handlerInput.responseBuilder.getResponse();
    }
};

const HelloIntentHandler = {
    canHandle(handlerInput) {
      return handlerInput.requestEnvelope.request.type === 'IntentRequest'
            && handlerInput.requestEnvelope.request.intent.name === 'HelloIntent';
    },
    handle(handlerInput) {
        const firstNameValue = Alexa.getSlotValue(handlerInput.requestEnvelope, 'FirstName')
        const greeting = getWish();
        const speechText = `Hello ${firstNameValue}. ${greeting}`

        return handlerInput.responseBuilder
            .speak(speechText)
            .reprompt(speechText)
            .withSimpleCard(TITLE_CARD, speechText)
            .getResponse();
    }
  };


let skill
exports.handler = async function (event, context) {
    console.log(`REQUEST++++${JSON.stringify(event)}`);
    if (!skill) {
        skill = Alexa.SkillBuilders.custom()
        .addRequestHandlers(
            LaunchRequestHandler,
            HelloIntentHandler,
            HelpIntentHandler,
            CancelAndStopIntentHandler,
            SessionEndedRequestHandler,
        )
        .addErrorHandlers(ErrorHandler)
        .create();
    }

    const response = await skill.invoke(event, context);
    console.log(`RESPONSE++++${JSON.stringify(response)}`);

    return response;
};