I'm sure this is a small configuration error, but I have followed the instructions for mailman3 and postfix. Basically mailman works fine, but confirmation emails, when answered by the subscriber or would-be subscriber, fails because 'listname' (after the '+something' is stripped off) is not a local user.
Also see my post to the postfix group: http://postfix.1071664.n5.nabble.com/address-extension-fails-for-mailman-td9....
Mind you, the postfix local_recipient_maps=regexp:/path/postfix_lmtp will correctly match any of the lists, but once the <+something> is added to the listname, it fails.
Note that I have configured a subdomain, klubb.domain.com, for my mailing lists.
First, my postfix.cf:
recipient_delimiter = +
smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu)
biff = no
append_dot_mydomain = no
readme_directory = no
smtpd_tls_cert_file=/etc/letsencrypt/live/mailer.example.com/cert.pem
smtpd_tls_key_file=/etc/letsencrypt/live/mailer.example.com/privkey.pem
smtpd_use_tls=yes
smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache
smtpd_helo_restrictions = permit_mynetworks, permit_sasl_authenticated
smtpd_sender_restrictions = permit_mynetworks, reject_non_fqdn_sender, reject_unknown_sender_domain
smtpd_recipient_restrictions = permit_mynetworks, permit_sasl_authenticated,
smtpd_tls_security_level = may
smtp_tls_security_level = may
smtp_tls_loglevel = 2
smtpd_tls_loglevel = 2
smtpd_relay_restrictions = permit_mynetworks, permit_sasl_authenticated, defer_unauth_destination
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128 172.19.199.0/24 <public.ip>/32
myhostname = mailer.example.com
mydomain = example.com
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
myorigin = mailer.example.com
mydestination = klubb.$mydomain, localhost.$mydomain, localhost, $myhostname, $mydomain
relayhost =
mailbox_size_limit = 0
inet_interfaces = all
inet_protocols = all
compatibility_level = 2
transport_maps = regexp:/opt/mailman/core/var/data/postfix_lmtp
local_recipient_maps = regexp:/opt/mailman/core/var/data/postfix_lmtp
relay_domains = regexp:/opt/mailman/core/var/data/postfix_domains
unknown_local_recipient_reject_code = 550
owner_request_special = no
propagate_unmatched_extensions = canonical, virtual, alias, forward, include
Here is the line in postfix mail.log where the valid listname+token is rejected: NOQUEUE: reject: RCPT from mail-lf0-f43.google.com[209.85.215.43]: 550 5.1.1 <abcliste-confirm+79ecdc9fe57e086b8e1335299ef5255d156b72db@klubb.example.com>: Recipient address rejected: User unknown in local recipient table; from=<me@mydomain.com> to=<abcliste-confirm+79ecdc9fe57e086b8e1335299ef5255d156b72db@klubb.example.com> proto=ESMTP helo=<mail-lf0-f43.google.com>
Any help will be appreciated.