Unable to find valid certification path to requested target and 'parent.relativePath' points at wrong local POM

Question

I am trying to build a proof of concept for microservices in java (eclipse) using maven Spring libraries and following this tutorial.

Below is my POM file, which shows an error, that I could not resolve:

<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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.tutorials</groupId>
  <artifactId>HelloWorld</artifactId>
  <version>0.0.1-SNAPSHOT</version>


<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>1.2.0.RELEASE</version>
</parent>

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>

</project>

On the tag <parent> I have the following error:

Project build error: Non-resolvable parent POM for com.tutorials:HelloWorld:0.0.1-SNAPSHOT: Failure to transfer org.springframework.boot:spring-boot-starter-parent:pom:
 1.2.0.RELEASE from https://repo.maven.apache.org/maven2 was cached in the local repository, resolution will not be reattempted until the update interval of central has 
 elapsed or updates are forced. Original error: Could not transfer artifact org.springframework.boot:spring-boot-starter-parent:pom:1.2.0.RELEASE from/to central (https://
 repo.maven.apache.org/maven2): sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to 
 find valid certification path to requested target and 'parent.relativePath' points at wrong local POM

How can I resolve this issue? Thanks.

Edit: In the directory User/.m2 I created a settings.xml file to overcome the proxy issue, as the following:

<settings>
  <proxies>
   <proxy>
      <id>example-proxy</id>
      <active>true</active>
      <protocol>http</protocol>
      <host>proxy.example.com</host>
      <port>8080</port>
      <nonProxyHosts>www.google.com|*.example.com</nonProxyHosts>
    </proxy>
  </proxies>
</settings>

Now the error is as the following:

Project build error: Non-resolvable parent POM for com.tutorials:HelloWorld:0.0.1-SNAPSHOT: Failure to transfer org.springframework.boot:spring-boot-starter-parent:pom:
 2.2.2.RELEASE from https://repo.maven.apache.org/maven2 was cached in the local repository, resolution will not be reattempted until the update interval of central has 
 elapsed or updates are forced. Original error: Could not transfer artifact org.springframework.boot:spring-boot-starter-parent:pom:2.2.2.RELEASE from/to central (https://
 repo.maven.apache.org/maven2): proxy.example.com and 'parent.relativePath' points at wrong local POM