SpringBootServletInitializer causes whitelabel error

I'm going through this online course about Spring MVC. During the course the instructor is adding a simple controller, and a simple jsp page. In addition the application class is extending SpringBootServletInitializer.

my index.html file is found in src/main/webapp and my jsp file is found in src/main/webapp/WEB-INF/jsp I've also added spring.mvc.view.prefix/suffix accordingly.

for some reason when i get to this point at the course, extending the SpringBootServletInitializer is causing whitelabel error to my main view (index.html) but the path to jsp file is working just fine.

I've tried some suggestions as changing @Controller to @RestController or removing the SpringBootServletInitializer but it didn't work (removing the SpringBootServletInitializer caused 404 when looking for the jsp page).

here is my code:

pom.xml:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.4.5</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.pluralSight</groupId>
    <artifactId>conference</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>war</packaging>
    <name>conference</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>11</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-tomcat</artifactId>
            <scope>provided</scope>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

controller:

package com.pluralSight.conference.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;


import java.util.Map;

@Controller
public class GreetingController {

    @GetMapping("greeting")
    public String greeting(Map<String, Object> model){
        model.put("message","Hello Daniel");
        return "greeting";
    }
}

application class:

package com.pluralSight.conference;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.servlet.support.SpringBootServletInitializer;

@SpringBootApplication
public class ConferenceApplication extends SpringBootServletInitializer{

    public static void main(String[] args) {
        SpringApplication.run(ConferenceApplication.class, args);
    }

}

application.properties:

spring.mvc.view.prefix=/WEB-INF/jsp/
spring.mvc.view.suffix=.jsp