已经挣扎了一天，找不到解决方案。当尝试向某些主机发送邮件时：
Jan 5 10:31:37 vps**** sm-mta[2192]: STARTTLS=client, relay=mail-x.*****.co.uk., version=TLSv1/SSLv3, verify=FAIL, cipher=DHE-RSA-AES256-SHA, bits=256/256
Jan 5 10:31:37 vps**** sm-mta[2192]: u059Vb4d002190: to=<****@****.co.uk>, ctladdr=<root@vps****.ovh.net> (0/0), delay=00:00:00, xdelay=00:00:00, mailer=esmtp, pri=124764, relay=mail-x.****.co.uk. [212.46.138.29], dsn=5.1.8, stat=Service unavailable
经过一番研究发现可能是TLS问题所以尝试禁用并添加：
Try_TLS: NO
但后来我得到：
Jan 5 10:33:56 vps**** sm-mta[2375]: ruleset=try_tls, arg1=mail-x.****.co.uk, relay=mail-x.****.co.uk, reject=550 5.7.1 <****@****.co.uk>... do not try TLS with mail-x.****.co.uk [212.46.138.29]
Jan 5 10:33:56 vps**** sm-mta[2375]: u059XuVY002373: to=<****@****.co.uk>, ctladdr=<root@vps****.ovh.net> (0/0), delay=00:00:00, xdelay=00:00:00, mailer=esmtp, pri=124764, relay=mail-x.****.co.uk. [212.46.138.29], dsn=5.1.8, stat=Service unavailable
我的 sendmail 版本和设置：Ubuntu 上的 8.14.4
============ SYSTEM IDENTITY (after readcf) …