说明：ss-panel-v3使用的SMTP发邮件，之前阿里云国际版用465端口正常，迁移到DigitalOcean不能使用25和465给客服发ticket，得到的回复如下：
[scode type="share"]Thank you for reaching out to us. We're very sorry that you are facing issues with SMTP.
Stopping spam is a constant fight and due to this, your account has restrictions specifically on ports 25 and 465. However, you are be able to send out mail using port 587. You will need to open the port in your firewall.
We realize this is inconvenient, but many customers in your position move their mailing activities to a third party service such as SendGrid or similar which processes such mail separately from their droplet. I'm sorry for the frustration but we're not able to lift these port restrictions at this time.
In terms of a workaround, here are a few alternatives:
- Utilize port 587 for SMTP relay via another mail provider, for example G Suite/Gmail, Mailgun, etc. We have a guide on doing so using Postfix here:
https://www.digitalocean.com/community/tutorials/how-to-set-up-a-mail-relay-with-postfix-and-mailgun-on-ubuntu-16-04
- Configure your app or service to send mail directly using either a SMTP client connection (typically using port 587), or API call via another mail provider such as Sendgrid, Mailgun, Mandrill, etc.
Please note that with this restriction in place on port 25, mail servers hosted here will be unable to directly relay email to other mail servers, as communication between mail servers typically takes place on port 25.
We think the API is the best solution, as it is honestly more scalable and what we would use if we wanted to "future proof" the project.
Please feel free to reach out to us via this ticket if you have further queries or concerns, we will be around to help you out!
Regards,
Saurabh
Developer Support Specialist - DigitalOcean
(Check out our fantastic community articles: https://www.digitalocean.com/community)[/scode]
所以决定使用Gmail的587来发送邮件。
开启IMAP
1.在计算机上打开 Gmail。
2.点击右上方的“设置”图标。
3.点击转发和 POP/IMAP 标签。
4.在“IMAP 访问”部分，点击启用 IMAP。
5.点击保存更改。
开启安全性较低的应用的访问权限
直达链接：https://myaccount.google.com/lesssecureapps
SMTP设置
发送邮件 (SMTP) 服务器：smtp.gmail.com
要求 SSL：是
要求 TLS：是（如适用）
使用身份验证：是
TLS/STARTTLS 端口：587
完整名称或显示名称：您的姓名
帐号名、用户名或电子邮件地址：您的完整电子邮件地址
密码：您的 Gmail 密码
