阿里云收购万网之后，几乎不赚钱的邮件服务还真是不维护不迭代了 — 不支持 DKIM，没法配 DMARC，就连 SMTP 也不支持 STARTTLS 587 端口。

# ...
receivers:
  - name: email
    email_configs:
      - send_resolved: true
        to: [email protected]
        from: [email protected]

        # ⬇ REQUIRED
        smarthost: smtp.qiye.aliyun.com:465
        require_tls: false
        hello: yourcompany.com
        # ⬆ REQUIRED

        auth_username: [email protected]
        auth_identity: [email protected]
        auth_password: ...

Reference