Jenkins pipelines: parallel execution

Jenkinsfile

pipeline {
  agent any
  
  stages {
    stage('SmokeTest'){
      parallel{
        stage('SmokeTest ProdEnv') {
          steps {
            echo 'Sanity Testing Production Environment',
            build job: 'smoke test',
            parameters: [[
              $class: 'StringParameterValue',
              name: 'TESTENV',
              value: 'production',
            ]]
          }		
        }
        stage('SmokeTest IntegEnv') {
		      steps {
		        echo 'Sanity Testing Integration Environment',
		        build job: 'smoke test',
			      parameters: [[
			        $class: 'StringParameterValue',
			        name: 'TESTENV',
			        value: 'integration',
			      ]]
		      }
		    }
		    stage('SmokeTest TestEnv') {
		      steps {
		        echo 'Sanity Testing Test Environment',
			      build job: 'smoke test',
			      parameters: [[
			        $class: 'StringParameterValue',
			        name: 'TESTENV',
			        value: 'test',
			      ]]
		      }
		    }
	    }
	  }
  }

  post{
    failure{
	    mail to: 's166205@hft-leipzig.de, stakeholder@company.com',
	    subject: "Failed Pipeline: ${currentBuild.fullDisplayName}",
	    body: "Something is wrong with ${env.BUILD_URL}"
	  }
  }
}