hello,
my multisite configuration doesn't work.
However I read official drupal tutorial.

I have this configuration :

/sites
     sites.php
    /default
        default.settings.php
        default.services.yml
    /catsuf.fr
        settings.php
        services.yml
    /boutique.catsuf.fr
        settings.php
        services.yml

In my sites.php :

$sites = array(
  "www.catsuf.fr"=>"catsuf.fr",
  "boutique.catsuf.fr"=>"boutique.catsuf.fr"
);

My site named catsuf.fr work but not boutique.catsuf.fr
I am redirecting to catsuf.fr when I go to boutique.catsuf.fr

My drupal installation is in my root

I did not change my .htaccess in root.

Idea ?

Thanks a lot !

PS: drupal 8.2.7