Subfolder in sieve not working as expected

[dovecot at ptld.com]

> On 11-15-2021 3:46 pm, Kees van Vloten wrote:
> 
> I am trying to move incoming mails into subfolders with this sieve script:
> 
> require ["fileinto", "variables", "mailbox"];
> if header :matches "Delivered-To" "*@*"
> {
>     fileinto :create "INBOX/${2}";
> }


I am not using variables and my folders are pre-created. But just to give you a starting point, this is what works using maildir++ format with default directory layout.
https://doc.dovecot.org/configuration_manual/mail_location/Maildir/

   require ["fileinto"];
   # rule:[Dovecot]
   if header :contains "sender" "@dovecot.org"
   {
      fileinto "INBOX.Dovecot";
   }