Web调试工具栏不显示symfony 3

I just follow this tutorial. I created a new controller but my web debug toolbar doesn't show up. I accessed it via app_dev.php file, like , myurl/web/app_dev/contact/ even if i access my url without the contact the web debug toolbar doesn't show up.

This is my config_dev.yml file:

imports:
    - { resource: config.yml }

framework:
    router:
        resource: "%kernel.root_dir%/config/routing_dev.yml"
        strict_requirements: true
    profiler: { only_exceptions: false }

web_profiler:
    toolbar: true
    intercept_redirects: false

monolog:
    handlers:
        main:
            type: stream
            path: "%kernel.logs_dir%/%kernel.environment%.log"
            level: debug
            channels: [!event]
        console:
            type:   console
            channels: [!event, !doctrine]
        # uncomment to get logging in your browser
        # you may have to allow bigger header sizes in your Web server configuration
        #firephp:
        #    type:   firephp
        #    level:  info
        #chromephp:
        #    type:   chromephp
        #    level:  info

#swiftmailer:
#    delivery_address: me@example.com

Do i need to do some extra settings ? I'm totally lost. Thx in advance.

Double check that you are actually accessing app_dev.php. For example try renaming app_dev.php to a new name 'app_dev_temp.php', then try reloading the page. If you can still access the page you are not where you think you are.

Also check your .htaccess file, if you are using a real server instead of the Symfony built in server, by default the htaccess will direct you to the app.php, not the dev version.