阿里云服务器25邮件端口问题

参考：https://www.cnblogs.com/jiafuwei/p/9512400.html

https://blog.csdn.net/qq_39455116/article/details/83865661

配置示例：

spring:
  mail:
    host: smtp.163.com
    username: 1111111@163.com
    password: aaaaaaaa
    default-encoding: UTF-8
    properties:
      mail:
        smtp:
          auth: true
          ssl:
            trust: smtp.163.com
          socketFactory:
            class: 'javax.net.ssl.SSLSocketFactory'
            port: 465
          starttls:
            enable: true
            required: true