Why can't I access my IntelliJ packages when building a project?

Question

I receive the following error whenever I run mvn clean install: "Can not access com.ludiaz.template."

Error Message

This error also occurs to me with other projects after I switched computers and re-downloaded IntelliJ on Ubuntu 20.04. I have checked that all my classes are set to public and have clicked Invalidate Caches/Restart countless amounts of times.

This is my project structure for the program that produced the error above: project structure. It is just a simple Spring Initializr app with only one function in the controller that returns "Hello."

EDIT:

This is my pom.xml file:

<?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>2.4.2</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.ludiaz</groupId>
    <artifactId>template</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>template</name>
    <description>Template made with Spring Initializr</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-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </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>
                <configuration>
                    <excludes>
                        <exclude>
                            <groupId>org.projectlombok</groupId>
                            <artifactId>lombok</artifactId>
                        </exclude>
                    </excludes>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

TemplateApplication.java:

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class TemplateApplication {

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

}

DemoController.java

package com.ludiaz.template.controller;

import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.ResponseBody;

@Slf4j
@Controller
public class DemoController {
    @ResponseBody
    @GetMapping("/demo")
    public String demo() {
        return "Hello Demo";
    }
}

Answer 1

It appears that some of my Spring dependencies were broken. I simply deleted my /home/.m2 folder and built the project again.