Get error with maven plugins

[natashayulian]

I already tried many suggest from websites, but it still give the same error. The error is like this:

Plugin org.codehaus.mojo:exec-maven-plugin:1.2.1 or one of its dependencies could not be resolved: Failed to read artifact descriptor for org.codehaus.mojo:exec-maven-plugin:jar:1.2.1: Could not transfer artifact org.codehaus.mojo:exec-maven-plugin:pom:1.2.1 from/to central (http://repo.maven.apache.org/maven2): Failed to transfer file: http://repo.maven.apache.org/maven2/org/codehaus/mojo/exec-maven-plugin/1.2.1/exec-maven-plugin-1.2.1.pom. Return code is: 501 , ReasonPhrase:HTTPS Required. -> [Help 1]

To see the full stack trace of the errors, re-run Maven with the -e switch.
Re-run Maven using the -X switch to enable full debug logging.