Postfix+Dovecot部署后Geary创建邮箱失败，Dovecot认证失败排查求助

大家好，我在Ubuntu Server 22.04（VMware Workstation 16虚拟机）上部署了Postfix+Dovecot邮件服务，然后在Ubuntu 22.04 Desktop上用Geary邮件客户端创建新邮箱时，一直提示“Account not created: check your sending server details”。查看服务器的/var/log/mail.log，发现了认证失败的日志，具体内容如下：

Jan 19 16:40:17 mailserver dovecot: imap-login: Disconnected: Connection closed (auth failed, 1 attempts in 4 secs): user=<obfuscated>, method=PLAIN, rip=192.168.0.220, lip=192.168.0.212, session=<JX+MEp7ymNTAqADc>

先说明下基础信息：

• 服务器主机名：mailserver.example.com
• 测试用户邮箱：obfuscateduser@example.com
• 未启用SSL/TLS加密

下面是我当前的各个配置文件内容，麻烦帮忙看看哪里出问题了：

Dovecot相关配置 #

/etc/dovecot/conf.d/10-mail.conf #

mail_location = mbox:~/mail:INBOX=/var/mail/%u
mail_location = maildir:~/Maildir
mail_privileged_group = mail

注：这里我写了两个mail_location，应该是最后一行的Maildir生效，但不确定会不会影响认证？

/etc/dovecot/dovecot.conf #

protocols = imap lmtp

/etc/dovecot/conf.d/10-master.conf #

service lmtp {
unix_listener /var/spool/postfix/private/dovecot-lmtp {
mode = 0600
user = postfix
group = postfix
}
}

service auth {
unix_listener /var/spool/postfix/private/auth {
mode = 0660
user = postfix
group = postfix
}
}

注：原配置里我不小心把service auth写成了ervice auth，已经修正过来了，不确定之前的笔误会不会有影响

/etc/dovecot/conf.d/10-auth.conf #

disable_plaintext_auth = no
auth_username_format = %n
auth_mechanisms = plain login

Postfix配置（/etc/postfix/main.cf） #

smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu)
biff = no
# appending .domain is the MUA's job.
append_dot_mydomain = no
readme_directory = no
compatibility_level = 3.6

# TLS parameters
smtpd_tls_cert_file=/etc/ssl/certs/ssl-cert-snakeoil.pem
smtpd_tls_key_file=/etc/ssl/private/ssl-cert-snakeoil.key
smtpd_tls_security_level=may
smtp_tls_CApath=/etc/ssl/certs
smtp_tls_security_level=may
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache

smtpd_relay_restrictions = permit_mynetworks permit_sasl_authenticated defer_unauth_destination
myhostname = mailserver.tne.com
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
myorigin = /etc/mailname
mydestination = $myhostname, example.com, mailserver.example.com, localhost.example.com, localhost
relayhost =
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128
mailbox_size_limit = 0
recipient_delimiter = +
inet_interfaces = all
inet_protocols = ipv4
message_size_limit = 52428800
mailbox_transport = lmtp:unix:private/dovecot-lmtp
smtputf8_enable = no

注：这里myhostname设置的是mailserver.tne.com，但实际服务器名称是mailserver.example.com，不确定这个不一致是否会导致问题？

服务器端口扫描结果（nmap） #

PORT    STATE  SERVICE
22/tcp  open   ssh
25/tcp  open   smtp
80/tcp  open   http
110/tcp closed pop3
143/tcp open   imap
443/tcp closed https
465/tcp closed smtps
587/tcp open   submission
993/tcp closed imaps
995/tcp closed pop3s

另外，我感觉可能需要补充用户相关的配置信息，但不知道具体应该看哪个文件，麻烦各位大佬帮忙排查下认证失败的原因，谢谢！

备注：内容来源于stack exchange，提问作者Ilya Shmadchenko