==== 必填信息。没有填写将不予回复 ====
- iRedMail 版本号：
- 使用哪个数据库存储用户帐号（OpenLDAP，MySQL，PostgreSQL）：
- 使用的 Linux/BSD 发行版名称及版本号：
- 与您的问题相关的日志信息：
==== ==== 必填信息。没有填写将不予回复 ====
- iRedMail 0.9.7：
- mysql
- ubuntu(lejmr/iredmail-docker)
- 阿里云ECS禁止出方向的25端口，所以打算通过587端口发送邮件。配置根据postfix官方文档，修改main.cf如下：
smtp_tls_security_level = encrypt
smtp_tls_wrappermode = yes
# The [] suppress MX lookups.
relayhost = [mail.xxx.xxx]:587

日志如下（打开了postfix详细日志）：

Apr 28 22:27:04 5f0549883af1 postfix/submission/smtpd[10632]: private/anvil: wanted attribute: count
Apr 28 22:27:04 5f0549883af1 postfix/submission/smtpd[10632]: input attribute name: count
Apr 28 22:27:04 5f0549883af1 postfix/submission/smtpd[10632]: input attribute value: 1
Apr 28 22:27:04 5f0549883af1 postfix/submission/smtpd[10632]: private/anvil: wanted attribute: rate
Apr 28 22:27:04 5f0549883af1 postfix/submission/smtpd[10632]: input attribute name: rate
Apr 28 22:27:04 5f0549883af1 postfix/submission/smtpd[10632]: input attribute value: 1
Apr 28 22:27:04 5f0549883af1 postfix/submission/smtpd[10632]: private/anvil: wanted attribute: (list terminator)
Apr 28 22:27:04 5f0549883af1 postfix/submission/smtpd[10632]: input attribute name: (end)
Apr 28 22:27:04 5f0549883af1 postfix/submission/smtpd[10632]: > mail.wuyad.top[47.94.168.163]: 220 mail.wuyad.top ESMTP Postfix
Apr 28 22:27:04 5f0549883af1 postfix/submission/smtpd[10632]: watchdog_pat: 0x55eeb42545d0
Apr 28 22:27:04 5f0549883af1 postfix/submission/smtpd[10632]: < mail.wuyad.top[47.94.168.163]: ????
Apr 28 22:27:04 5f0549883af1 postfix/submission/smtpd[10632]: > mail.wuyad.top[47.94.168.163]: 500 5.5.2 Error: bad UTF-8 syntax
Apr 28 22:27:04 5f0549883af1 postfix/submission/smtpd[10632]: watchdog_pat: 0x55eeb42545d0
Apr 28 22:27:04 5f0549883af1 postfix/submission/smtpd[10632]: < mail.wuyad.top[47.94.168.163]:
Apr 28 22:27:04 5f0549883af1 postfix/submission/smtpd[10632]: > mail.wuyad.top[47.94.168.163]: 500 5.5.2 Error: bad UTF-8 syntax
Apr 28 22:27:04 5f0549883af1 postfix/submission/smtpd[10632]: watchdog_pat: 0x55eeb42545d0
Apr 28 22:27:04 5f0549883af1 postfix/submission/smtpd[10632]: < mail.wuyad.top[47.94.168.163]:
Apr 28 22:27:04 5f0549883af1 postfix/submission/smtpd[10632]: > mail.wuyad.top[47.94.168.163]: 500 5.5.2 Error: bad UTF-8 syntax
Apr 28 22:27:04 5f0549883af1 postfix/submission/smtpd[10632]: watchdog_pat: 0x55eeb42545d0
Apr 28 22:27:04 5f0549883af1 postfix/submission/smtpd[10632]: < mail.wuyad.top[47.94.168.163]:
Apr 28 22:27:04 5f0549883af1 postfix/submission/smtpd[10632]: > mail.wuyad.top[47.94.168.163]: 500 5.5.2 Error: bad syntax
Apr 28 22:27:04 5f0549883af1 postfix/submission/smtpd[10632]: watchdog_pat: 0x55eeb42545d0
Apr 28 22:27:04 5f0549883af1 postfix/smtp[10645]: SSL_connect error to mail.wuyad.top[47.94.168.163]:587: -1
Apr 28 22:27:04 5f0549883af1 postfix/smtp[10645]: warning: TLS library problem: error:140770FC:SSL routines:SSL23_GET_SERVER_HELLO:unknown protocol:s23_clnt.c:794:
Apr 28 22:27:04 5f0549883af1 postfix/smtp[10645]: connect to subsystem private/defer
Apr 28 22:27:04 5f0549883af1 postfix/smtp[10645]: send attr nrequest = 0
Apr 28 22:27:04 5f0549883af1 postfix/smtp[10645]: send attr flags = 0
Apr 28 22:27:04 5f0549883af1 postfix/smtp[10645]: send attr queue_id = F010BA6B14
Apr 28 22:27:04 5f0549883af1 postfix/smtp[10645]: send attr original_recipient =
Apr 28 22:27:04 5f0549883af1 postfix/smtp[10645]: send attr recipient = alex_wuya@163.com
Apr 28 22:27:04 5f0549883af1 postfix/smtp[10645]: send attr offset = 613
Apr 28 22:27:04 5f0549883af1 postfix/smtp[10645]: send attr dsn_orig_rcpt = rfc822;alex_wuya@163.com
Apr 28 22:27:04 5f0549883af1 postfix/smtp[10645]: send attr notify_flags = 0
Apr 28 22:27:04 5f0549883af1 postfix/smtp[10645]: send attr status = 4.7.5
Apr 28 22:27:04 5f0549883af1 postfix/smtp[10645]: send attr diag_type =
Apr 28 22:27:04 5f0549883af1 postfix/smtp[10645]: send attr diag_text =
Apr 28 22:27:04 5f0549883af1 postfix/smtp[10645]: send attr mta_type =
Apr 28 22:27:04 5f0549883af1 postfix/smtp[10645]: send attr mta_mname =
Apr 28 22:27:04 5f0549883af1 postfix/smtp[10645]: send attr action = delayed
Apr 28 22:27:04 5f0549883af1 postfix/smtp[10645]: send attr reason = Cannot start TLS: handshake failure
Apr 28 22:27:04 5f0549883af1 postfix/smtp[10645]: private/defer socket: wanted attribute: status
Apr 28 22:27:04 5f0549883af1 postfix/smtp[10645]: input attribute name: status
Apr 28 22:27:04 5f0549883af1 postfix/smtp[10645]: input attribute value: 0
Apr 28 22:27:04 5f0549883af1 postfix/smtp[10645]: private/defer socket: wanted attribute: (list terminator)
Apr 28 22:27:04 5f0549883af1 postfix/smtp[10645]: input attribute name: (end)
Apr 28 22:27:04 5f0549883af1 postfix/smtp[10645]: F010BA6B14: to=<alex_wuya@163.com>, relay=mail.wuyad.top[47.94.168.163]:587, delay=0.06, delays=0.03/0.01/0.01/0, dsn=4.7.5, status=deferred (Cannot start TLS: handshake failure)

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请问题该如何排查？