如果發送電郵到 Gmail 收到以下退信
The IP address sending this message does not have a
5.7.25 PTR record setup, or the corresponding forward DNS entry does not
5.7.25 point to the sending IP. As a policy, Gmail does not accept messages
5.7.25 from IPs with missing PTR records. Please visit
5.7.25 https://support.google.com/mail/answer/81126#ip-practices for more
代表閣下VDS或獨立主機未有設定好PTR紀錄，請電郵至 support@scicube.com 聯絡我們安排處理
如果發送電郵到 Gmail 收到以下退信
Our system has detected an unusual rate of
421-4.7.28 unsolicited mail originating from your IP address. To protect our
421-4.7.28 users from spam, mail sent from your IP address has been temporarily
421-4.7.28 rate limited. Please visit
421-4.7.28 https://support.google.com/mail/?p=UnsolicitedRateLimitError to
421 4.7.28 review our Bulk Email Senders Guidelines.
主要可能性是未有設定好SPF紀錄，一般情況下我們已經預設設定好，但部分客戶域名未有使用我提供的DNS/Name Server便需要查看一下自己的DNS有沒有設定適當的SPF紀錄
scicube的預設SPF紀錄爲
"v=spf1 a mx include:pointdnshere.com ~all"
如果使用其它公司DNS (如wix)，請確保TXT 紀錄有加入以上SPF紀錄。如果本身有其它公司的SPF紀錄請先刪除，如果已經加入但仍然收到退信請電郵至 support@scicube.com 聯絡我們安排處理，謝謝。