qq域名邮箱已开启 smtp ，smtp.qq.com 25 。
但是本地测试却无法发送邮件，报错提示：

 Error Info : SMTP connect() failed. 
https://github.com/PHPMailer/PHPMailer/wiki/Troubleshooting
Host: smtp.qq.com

telnet

 Last login: Fri Sep  4 23:26:09 on ttys003
ben:~ soul$ telnet smtp.qq.com 25
Trying 14.17.57.241...
Connected to smtp.qq.com.
Escape character is '^]'.
220 smtp.qq.com Esmtp QQ Mail Server
^C

Connection closed by foreign host.
ben:~ soul$

如上的 telnet是说明链接上了还是未连接上, ping smtp.qq.com 是返回的