Good afternoon. There is a mail server (smtp relay) on ubuntu 22.04. This is the core of the server. There are mail accounts on Google Workspace, and the transfer of outgoing letters from these accounts to the created smtp server is configured. Everything is sent from corporate mail(Google workspace) without problems, the relay works correctly. However, when I try to send mail (from any mailbox) to a corporate mailbox, I get an error "mail for example.com loops back to myself".
I provide my server configuration.
Ubuntu 22.04
Postfix version 3.6.4
Could you suggest what is the problem?
Thank you
main.cf
# See /usr/share/postfix/main.cf.dist for a commented, more complete version
# Debian specific: Specifying a file name will cause the first
# line of that file to be used as the name. The Debian default
# is /etc/mailname.
#myorigin = /etc/mailname
smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu)
biff = no
# appending .domain is the MUA's job.
append_dot_mydomain = no
# Uncomment the next line to generate "delayed mail" warnings
#delay_warning_time = 4h
readme_directory = no
# See http://www.postfix.org/COMPATIBILITY_README.html -- default to 3.6 on
# fresh installs.
compatibility_level = 3.6
# TLS parameters
smtpd_tls_cert_file=/etc/letsencrypt/live/example.com/fullchain.pem
smtpd_tls_key_file=/etc/letsencrypt/live/example.com/privkey.pem
smtpd_tls_security_level=may
smtp_use_tls=yes
smtp_tls_CApath=/etc/ssl/certs
smtp_tls_security_level=may
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache
smtpd_sender_restrictions = permit_sasl_authenticated, permit_mynetworks, check_relay_domains
myhostname = mail.example.com
mydomain = mail.example.com
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
mydestination = $myhostname, localhost.$mydomain, localhost, example.com
relayhost =
relay_domains = gmail.com, google.com, mail.example.com
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128 35.190.247.0/24 64.233.160.0/19 66.102.0.0/20 66.249.80.0/20 72.14.192.0/18 74.125.0.0/16 108.177.8.0/21 173.194.0.0/16 209.85.128.0/17 216.58.192.0/19 216.239.32.0/19 [2001:4860:4000::]/36 [2404:6800:4000::]/36 [2607:f8b0:4000::]/36 [2800:3f0:4000::]/36 [2a00:1450:4000::]/36 [2c0f:fb50:4000::]/36 172.217.0.0/19 172.217.32.0/20 172.217.128.0/19 172.217.160.0/20 172.217.192.0/19 172.253.56.0/21 172.253.112.0/20 108.177.96.0/19 35.191.0.0/16 130.211.0.0/22
mailbox_size_limit = 0
recipient_delimiter = +
inet_interfaces = all
inet_protocols = ipv4
milter_protocol = 2
milter_default_action = accept
smtpd_milters = inet:localhost:8891
non_smtpd_milters = inet:localhost:8891
DNS domain records:
example.com
MX
5 alt2.aspmx.l.google.com.
5 alt1.aspmx.l.google.com
10 alt4.aspmx.l.google.com.
2 aspmx.l.google.com.
10 alt3.aspmx.l.google.com.
1 mail.example.com
mail.example.com
A
0.0.0.0(example)
