java.lang.UnsupportedOperationException: no known implementation of class jenkins.tasks.SimpleBuildWrapper is named BuildUser in jenkins I preparing script in Jenkins as below where I getting error while build job. This job is send email to user for input for next step.
 [Pipeline] End of Pipeline
 java.lang.UnsupportedOperationException: no known implementation of class jenkins.tasks.SimpleBuildWrapper is named BuildUser
    at org.jenkinsci.plugins.structs.describable.DescribableModel.resolveClass(DescribableModel.java:549)
    at org.jenkinsci.plugins.structs.describable.DescribableModel.coerce(DescribableModel.java:473)
    ...
    ...

Version :
$ java --version
 openjdk 11.0.11 2021-04-20

jenkins : 2.277.3

Pipeline code:
def user
node {
wrap([$class: 'BuildUser']) {
user = env.BUILD_USER_ID
}

emailext mimeType: 'text/html',
             subject: &quot;[Jenkins]${currentBuild.fullDisplayName}&quot;,
             to: &quot;user@xxx.com&quot;,
             body: '''&lt;a href=&quot;${BUILD_URL}input&quot;&gt;click to approve&lt;/a&gt;'''
}

pipeline {
agent any
stages {
    stage('deploy') {
        input {
            message &quot;Should we continue?&quot;
            ok &quot;Yes&quot;
        }
        when {
            expression { user == 'hardCodeApproverJenkinsId'}
        }
        steps {
            sh &quot;echo 'describe your deployment' &quot;
        }
    }
   }
}

Can anyone please review this, please ?
Have you installed the Build User Vars Plugin? This plugin provides the &quot;BuildUser&quot; class.