Hi, I have postfix running and sometimes and I have some duplicate emails with the same Message-ID. With dovecot sieve, I understand that duplicate option remove these emails but I don't understand the configuration to apply. Thanks for your tips,

# doveconf -n # 2.3.7.2 (3c910f64b): /etc/dovecot/dovecot.conf # Pigeonhole version 0.5.7.2 () # OS: Linux 5.4.0-104-generic x86_64 Ubuntu 20.04.4 LTS # Hostname: B7B3274.online-server.cloud auth_mechanisms = plain login first_valid_uid = 8 log_path = /var/log/dovecot.log mail_location = maildir:~ managesieve_notify_capability = mailto managesieve_sieve_capability = fileinto reject envelope encoded-character vacation subaddress comparator-i;ascii-numeric relational regex imap4flags copy include variables body enotify environment mailbox date index ihave duplicate mime foreverypart extracttext namespace inbox { inbox = yes location = mailbox Drafts { special_use = \Drafts } mailbox Junk { special_use = \Junk } mailbox Sent { special_use = \Sent } mailbox "Sent Messages" { special_use = \Sent } mailbox Trash { special_use = \Trash } prefix = } passdb { args = /etc/dovecot/dovecot-sql.conf.ext driver = sql } plugin { sieve = ~/.dovecot.sieve sieve_dir = ~/sieve } protocols = imap service auth { unix_listener /var/spool/postfix/private/dovecot-auth { group = postfix mode = 0660 user = postfix } } ssl_cert = </etc/letsencrypt/live/mail.maxou.fr/fullchain.pem ssl_cipher_list = ALL:!LOW:!SSLv2:ALL:!aNULL:!ADH:!eNULL:!EXP:RC4+RSA:+HIGH:+MEDIUM ssl_client_ca_dir = /etc/ssl/certs ssl_key = # hidden, use -P to show it userdb { args = /etc/dovecot/dovecot-sql.conf.ext driver = sql } protocol imap { imap_client_workarounds = delay-newmail mail_max_userip_connections = 50 } protocol pop3 { mail_max_userip_connections = 10 pop3_client_workarounds = outlook-no-nuls oe-ns-eoh } protocol lda { deliver_log_format = msgid=%m: %$ mail_plugins = sieve postmaster_address = postmaster quota_full_tempfail = yes rejection_reason = Your message to <%t> was automatically rejected:%n%r }