Erro na tag "parent" do modelo importada da alura

Fiz a importação do modelo de projeto, mas, não consigo fazer os exercícios, pois, a tag "parent" apresenta o erro:

Project build error: Non-resolvable parent POM for br.com.alura:forum:0.0.1-SNAPSHOT: Failure to transfer 
 org.springframework.boot:spring-boot-starter-parent:pom:2.1.4.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:2.1.4.RELEASE from/to central (https://
 repo.maven.apache.org/maven2): Connection reset and 'parent.relativePath' points at no local POM.

A tag importada foi :

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.3.4.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

No site do spring initialize não existia a versão do spring boot 2.1.4 mencionado no curso e inicialmente importei a versão default 2.3.4.