Already solved here: http://www.iredmail.org/forum/post478.html#p478

Thanks a lot!

It's embarrassing. Normally I'm pretty good with the search function.

Best regards!

again a problem with sieve.

Dovecot (responsible?) doesn't create the sieve directory for new users.
The maildir is created perfectly.

Where do I look for errors in the configuration?

my dovecot.conf
plugin {
    # NOTE: %variable expansion works only with Dovecot v1.0.2+.
    # For maildir format.
    sieve = /home/vmail/sieve/%Ld/%Ln/.dovecot.sieve
}   
   
# LDA: Local Deliver Agent
protocol lda {
     postmaster_address = root
    auth_socket_path = /var/run/dovecot/auth-master
    mail_plugins = cmusieve quota
    sieve_global_path = /home/vmail/.dovecot.sieve
    log_path = /var/log/sieve.log
    debug=yes
}

Help appreciated!
Thanks!

Nylan