Dovecot提交服务：身份验证失败

我在使用 Dovecot + Postfix 设置提交时遇到问题。

doveadm auth login user pass给出正确的输出。

当我尝试发送带有提交的邮件时，它给出身份验证失败错误。

doveconf -n输出：

auth_mechanisms = plain login
disable_plaintext_auth = no
mail_location = maildir:/home/vmail/%d/%n
mail_privileged_group = vmail
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
}
protocols = " imap lmtp submission"
service auth {
  unix_listener /var/spool/postfix/private/auth {
    group = postfix
    mode = 0666
    user = postfix
  }
}
service lmtp {
  unix_listener /var/spool/postfix/private/lmtp {
    group = postfix
    mode = 0600
    user = postfix
  }
}
ssl_cert = < some_crt
ssl_client_ca_dir = /etc/ssl/certs
ssl_dh = # hidden, use -P to show it
ssl_key = # hidden, use -P to show it
userdb {
  args = /etc/dovecot/dovecot-sql.conf.ext
  driver = sql
}