Cannot resolve plugin org.springframework.boot:spring-boot-maven-plugin:<unknown> Try to run Maven import with -U flag (force update snapshots)

This error message suggests that Maven is unable to resolve the version of the Spring Boot Maven plugin that you have specified in your project's POM file.

One potential solution is to run the Maven import command with the "-U" flag, which will force Maven to update its snapshot repository and download any missing dependencies. You can do this by running the following command in your project's root directory:

mvn clean install -U

If this does not resolve the issue, then you may need to check your project's POM file and ensure that the version of the Spring Boot Maven plugin is correct and matches the version of Spring Boot that you are using. You can also try removing the version number from the plugin definition and letting Maven use the default version for your project's Spring Boot version.