frontend/controllers/apix/SiteController.php
public function actionSignUp() {

		// Create Form Model
		$model = new SignUpForm();

		// Load and Validate Form Model
		if( $model->load( Yii::$app->request->post(), 'Newsletter' ) && $model->validate() ) {

			if( $this->newsletterMemberService->signUp( $model ) ) {

				// Trigger Ajax Success
				return AjaxUtil::generateSuccess( Yii::$app->newsletterMessage->getMessage( NewsletterGlobal::MESSAGE_NEWSLETTER_SIGNUP ) );
			}
		}

		// Generate Errors
		$errors = AjaxUtil::generateErrorMessage( $model );

		// Trigger Ajax Failure
		return AjaxUtil::generateFailure( Yii::$app->coreMessage->getMessage( CoreGlobal::ERROR_REQUEST ), $errors );
	}
public function actionSignUp() {

		// Create Form Model
		$model = new SignUpForm();

		// Load and Validate Form Model
		if( $model->load( Yii::$app->request->post(), 'Newsletter' ) && $model->validate() ) {

			if( $this->newsletterMemberService->signUp( $model ) ) {

				// Trigger Ajax Success
				return AjaxUtil::generateSuccess( Yii::$app->newsletterMessage->getMessage( NewsletterGlobal::MESSAGE_NEWSLETTER_SIGNUP ) );
			}
		}

		// Generate Errors
		$errors = AjaxUtil::generateErrorMessage( $model );

		// Trigger Ajax Failure
		return AjaxUtil::generateFailure( Yii::$app->coreMessage->getMessage( CoreGlobal::ERROR_REQUEST ), $errors );
	}
SiteController ------------------------