postfix-警告：トランスポートprivate / smtpに接続：接続が拒否されました
Postfix + dovecotメールサーバーで問題が発生しています。別のサーバー（Gmailなど）にメールを送信しようとすると、ログに次のメッセージが表示されます。
postfix/qmgr[28918]: warning: connect to transport private/smtp: Connection refused
postfix/error[29298]: BB36617ABFB: to=<[email protected]>, relay=none, delay=575, delays=575/0.01/0/0.01, dsn=4.3.0, status=deferred (mail transport unavailable)
どういうわけか、postfixはポストスクリーントランスポートに接続できません。これは私のmain.cfです（ドメインが置き換えられています）：
## These are all default Postfix settings that we won't change
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
append_dot_mydomain = no
biff = no
broken_sasl_auth_clients = yes
inet_protocols = ipv4, ipv6
inet_interfaces = all
mailbox_command = /usr/lib/dovecot/deliver -c /etc/dovecot/conf.d/99-mail-stack-delivery.conf -m "${EXTENSION}"
mailbox_size_limit = 0
readme_directory = no
recipient_delimiter = +
relayhost =
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache
smtpd_sasl_auth_enable = yes
smtpd_sasl_authenticated_header = yes
smtpd_sasl_path = private/dovecot-auth
smtpd_sasl_security_options = noanonymous
smtpd_sasl_local_domain = $myhostname
smtpd_sasl_type = dovecot
smtpd_tls_auth_only = yes
smtpd_tls_received_header = yes
smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
tls_random_source = dev:/dev/urandom
## Settings below this line are things we're modifying or adding
## Your mail server identity options
myhostname = domain1.com
mydestination = mail.domain1.com, localhost, mx.domain1.com
mynetworks = 127.0.0.0/8 10.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128 172.17.0.0/16
## Customized smtpd paramters
smtpd_banner = $myhostname ESMTP
smtpd_helo_required = yes
smtpd_helo_restrictions = permit_mynetworks, reject_non_fqdn_helo_hostname, reject_invalid_helo_hostname, reject_unknown_helo_hostname, permit
smtpd_recipient_restrictions = permit_mynetworks, reject_unknown_sender_domain, reject_unknown_recipient_domain, reject_unauth_pipelining, permit_sasl_authenticated, reject_unauth_destination, reject_invalid_hostname, reject_non_fqdn_sender
smtpd_sender_restrictions = permit_mynetworks, reject_unknown_sender_domain, reject_sender_login_mismatch
smtpd_sender_login_maps = $virtual_mailbox_maps
## Dealing with rejection: use permanent 550 errors to stop retries
unknown_address_reject_code = 550
unknown_hostname_reject_code = 550
unknown_client_reject_code = 550
## customized TLS parameters
smtpd_tls_ask_ccert = yes
smtpd_tls_cert_file = somewhere.crt
smtpd_tls_key_file = somewhere.key
smtpd_tls_CAfile = /etc/ssl/certs/ca-certificates.crt
smtpd_tls_ciphers = high
smtpd_tls_loglevel = 1
smtpd_tls_security_level = may
smtpd_tls_session_cache_timeout = 3600s
## Customized Dovecot and virtual user-specific settings
canonical_maps = hash:/etc/postfix/canonical
home_mailbox = Maildir/
message_size_limit = 104857600
virtual_alias_maps = hash:/etc/postfix/virtual
virtual_alias_domains = hash:/etc/postfix/virtual-mailbox-domains
virtual_mailbox_maps = hash:/etc/postfix/virtual-mailbox-users
virtual_transport = dovecot
## This setting will generate an error if you restart Postfix before
## adding the appropriate service definition in master.cf, so make
## sure to get that taken care of!
dovecot_destination_recipient_limit = 1
## Customized milter settings
milter_default_action = accept
milter_connect_macros = j {daemon_name} v {if_name} _
non_smtpd_milters = $smtpd_milters
smtpd_milters = unix:/var/spool/postfix/spamass/spamass.sock unix:/var/spool/postfix/opendkim/opendkim.sock
## Other customized mail server settings
default_destination_concurrency_limit = 5
disable_vrfy_command = yes
relay_destination_concurrency_limit = 1
smtp_tls_note_starttls_offer = yes
smtp_tls_security_level = may
postscreen_greet_action = enforce
postscreen_dnsbl_action = enforce
postscreen_access_list = permit_mynetworks
postscreen_dnsbl_sites = zen.spamhaus.org, b.barracudacentral.org, bl.spamcop.net
myorigin = $myhostname
そして私のmaster.cf：
# ==========================================================================
# service type private unpriv chroot wakeup maxproc command + args
# (yes) (yes) (no) (never) (100)
# ==========================================================================
smtp inet n - n - 1 postscreen
smtpd pass - - n - - smtpd
dnsblog unix - - n - 0 dnsblog
tlsproxy unix - - n - 0 tlsproxy
submission inet n - n - - smtpd
-o syslog_name=postfix/submission
-o smtpd_tls_security_level=encrypt
-o smtpd_sasl_auth_enable=yes
-o smtpd_relay_restrictions=permit_sasl_authenticated,reject
-o milter_macro_daemon_name=ORIGINATING
pickup unix n - n 60 1 pickup
cleanup unix n - n - 0 cleanup
qmgr unix n - n 300 1 qmgr
tlsmgr unix - - n 1000? 1 tlsmgr
rewrite unix - - n - - trivial-rewrite
bounce unix - - n - 0 bounce
defer unix - - n - 0 bounce
trace unix - - n - 0 bounce
verify unix - - n - 1 verify
flush unix n - n 1000? 0 flush
proxymap unix - - n - - proxymap
proxywrite unix - - n - 1 proxymap
relay unix - - n - - smtp
showq unix n - n - - showq
error unix - - n - - error
retry unix - - n - - error
discard unix - - n - - discard
local unix - n n - - local
virtual unix - n n - - virtual
lmtp unix - - n - - lmtp
anvil unix - - n - 1 anvil
scache unix - - n - 1 scache
maildrop unix - n n - - pipe
flags=DRhu user=vmail argv=/usr/local/bin/maildrop -d ${recipient}
dovecot unix - n n - - pipe
flags=DRhu user=mail:mail argv=/usr/lib/dovecot/deliver
-f ${sender} -d ${user}@${nexthop} -a ${recipient}
virtual-mailbox-domains：
domain1.com OK
domain2.net OK
私のサーバーもIPv6を実行していますが、それが何かに関係しているかどうかはわかりません。さらに情報が必要な場合は、コメントをドロップしてください;）
前もって感謝します。
結局のところ、ライン
smtp unix - - n - - smtp
ポストマップから重複した警告が必要だったのでコメントアウトしました。そこに戻すだけで動作し始めました。