只是copy the above code and paste it into your theme’s functions.php file. 在这里，我将向您展示will reject registration from all others email addresses 和Only allowing some email addresses to create an account. 请参见下面的代码

function is_valid_emails($login, $email, $errors ){
     $valid_emails = array("[email protected]");
     $valid = false;
     foreach( $valid_emails as $valid_email ){
         $valid_emails_list = strtolower($valid_email);
         $current_email = strtolower($email);
         if( $current_email == $valid_emails_list ){
         $valid = true;
            break;
         }
     }
     if( $valid === false ){
        $errors->add(\'domain_whitelist_error\',__( "<strong>ERROR</strong>: you can\'t register email because only allow some specific email addresses" ));
     }
    }
    add_action(\'register_post\', \'is_valid_emails\',10,3 );

$valid_emails = array("[email protected]","[email protected]");

不应使用register\\u post操作，而应使用如下registration\\u errors筛选器（从codex复制，然后修改）：

function my_awesome_email_validation_filter( $errors, $sanitized_user_login, $user_email ) {
     $allowed_email_addresses = array(\'[email protected]\',\'[email protected]\');    //be sure to write all the allowed addresses in lowercase
     if(!in_array(mb_strotolower($user_email),$allowed_email_addresses)){
          $errors->add( \'email_not_allowed\', __( \'<strong>ERROR</strong>: Sorry, but you are not allowed to register.\', \'my_textdomain\' ) );
     }
    return $errors;
}

add_filter( \'registration_errors\', \'my_awesome_email_validation_filter\', 10, 3 );

https://wordpress.org/plugins/wp-approve-user/ 是一个插件，允许您在允许用户登录您的网站之前批准用户注册。在管理员用户批准之前，所有用户注册基本上都处于挂起状态。

插件woocommerce成员身份可以做到这一点。但仅此功能就很昂贵。最好使用上面建议的代码。