Symfony2 Monolog到电子邮件错误为什么swiftmailer.transport.real不存在

从更新symfony后2.3，2.4我得到了ServiceNotFoundException

 Fatal error: Uncaught exception 'Symfony\Component\DependencyInjection\Exception\ServiceNotFoundException' with message 'The service "monolog.handler.mojhandler" has a dependency on a non-existent service "swiftmailer.transport.real".' in E:\wamp\www\project\vendor\symfony\symfony\src\Symfony\Component\DependencyInjection\Compiler\CheckExceptionOnInvalidReferenceBehaviorPass.php on line 59

这是我的config_prod.yml

imports:
    - { resource: config.yml }
monolog:
    handlers:
        main:
            type:         fingers_crossed
            action_level: error
            handler:      streamed
        streamed:
            type:  stream
            path:  %kernel.logs_dir%/%kernel.environment%.log
            level: debug
        mail:
            type:         fingers_crossed
            action_level: error
            handler:      buffered
            channels: ["!app"] # Dont log app because we dont' want 404 errors sending
        buffered:
            type:    buffer
            handler: mojhandler
        mojhandler:
            type:       swift_mailer
            from_email: %mojhandler_logger_email%
            to_email:   %mojhandler_logger_email%
            subject:    "[Panel] An Error Occurred!"
            level:      debug

这是来自config.yml的我的swiftmailer配置

# Swiftmailer Configuration
swiftmailer:
    transport: %mailer_transport%
    host:      %mailer_host%
    username:  %mailer_user%
    password:  %mailer_password%
    port:      %mailer_port%
    auth_mode: %mailer_auth_mode%
    encryption: %mailer_encryption%

我该如何解决？