我在 Ubuntu 18.04 lts 上安装了 Postfix，并尝试使用 PHP 邮件功能发送邮件。我在 mail.log 中得到的内容如下。有人能在日志输出中看到问题吗？
Jan 27 16:27:23 dv7 postfix/pickup[16608]: 42333FA29A3: uid=33 from=<www-data>
Jan 27 16:27:23 dv7 postfix/cleanup[16653]: 42333FA29A3: message-id=<20200127232723.42333FA29A3@dv7>
Jan 27 16:27:23 dv7 postfix/qmgr[16187]: 42333FA29A3: from=<[email protected]>, size=476, nrcpt=1 (queue active)
Jan 27 16:27:54 dv7 postfix/smtp[16655]: connect to mx5.mail.icloud.com[17.172.34.69]:25: Connection timed out
Jan 27 16:28:24 dv7 postfix/smtp[16655]: connect to mx1.mail.icloud.com[17.172.34.9]:25: Connection timed out
Jan 27 16:28:54 dv7 postfix/smtp[16655]: connect to mx6.mail.icloud.com[17.172.34.70]:25: Connection timed out