[2022.LEARN.014][筆記]Sendgrid發送信件的狀態

參考：

• https://docs.sendgrid.com/ui/analytics-and-reporting/email-activity-feed
• https://sendgrid.com/blog/the-nine-events-of-email/
• https://www.activecampaign.com/blog/email-bounce
• https://www.socialmediatoday.com/content/8-reasons-emails-bounce

原文：

• Processed：
• Requests from your website, application, or mail client via SMTP Relay or the API that SendGrid processed.
• 當SendGridAPI新增將觸發此事件，(第一個事件)，除非信件被判斷為dropped。
• Clicks：
• Whenever a recipient clicks one of the Click Tracked links in your email. In the Email History, SendGrid displays the date, time, and the URL for the link that was clicked.
• 信件連結被點擊了。（理論上應該是收到信才有可能觸發）
• Delivered
• The accepted response generated by the recipients' mail server.
• 此事件不保證接收伺服器接收到信件，只是標記已經傳送信件。
• 後續還有相關狀態回報。
• Delivered、Bounced、Blocked、Deffered
• Opens
• The response generated by a recipient opening an email.
• 信件被打開了。（理論上應該是收到信才會打開）
• Unsubscribes
• Whenever a recipient unsubscribes from your emails.
• Group Unsubscribes
• Whenever a recipient unsubscribes from a suppression group.
• Group Resubscribes
• When a recipient resubscribes themselves to a suppression group.
• 
  
• Deferred
• The recipient mail server asked SendGrid to stop sending emails so fast.
• 收件郵件伺服器要求SendGridd停止短時間快速送信。
• Drops
• SendGrid will drop an email when the contact on that email is in one of your suppression groups, the recipient email previously bounced, or that recipient has marked your email as spam.
• SendGrid將會【Drop】信件的幾種情況。
• 當你的聯絡人Email在黑名單(禁止群)中。
• 或是該收件人之前被【bounce】。
• 或是email被收件人標記為垃圾郵件。
• Bounces
• The receiving server could not or would not accept the message. If a recipient has previously unsubscribed from your emails, your attempt to send to them is bounced.
• 接收服務器無法接收此訊息。
• 如果收件人之前已取消訂閱您的電子郵件，您發送給他們的郵件將被【bounce】退回。
• 常見：
• 軟退回:可能臨時無法寄送成功，會嘗試重送。
• 郵箱已滿。
• 夾檔附件太大。
• 伺服器以關閉。
• 收件方啟用自動回覆。
• 硬退回:無效的電子郵件，不重送。
• 假信箱：故意提供假的信箱。
• 驗證規則可能就可以判斷。
• 不正確：打錯了。
• 不小心拚打錯，驗證可能可以通過。
• abc@gmail.com->abv@gmail.com
• 被阻止：政府機關可能會擋某些網域的郵件。
• 可能要加入白名單之類。
• 黑名單:被列入黑名單。
• 8個原因：
• 垃圾郵件過濾器
• 被管理者擋掉(Individual Server Administrators)
• 主題出現「免費」、「訂閱」、類似詐騙信件、只有主旨沒有內容等。
• Subject starts with “Free”
• Contains, “If you want to subscribe...”
• Offers a full refund
• Claims you have provided permission
• “See for yourself”
• Subject is all capitals
• Message is 0% to 10% HTML
• HTML title contains no text
• “Free Preview”
• 自然消亡(Natural Database Decay):企業，離職或是網域消失。
• 臨時無法交付(Temporary Un-deliverables):信箱滿了，夾黨太大，臨時狀況拒絕電子郵件，會發生軟退回(退回重送)。
• 無效地址(Invalid Addresses):地址無效，發生硬退回(不重送)。
• 不小心打錯或是故意填錯。
• 發信人信譽(Sender Reputation)：網域或郵件不被信任。
• 列入黑名單ip(Blacklisted IP Ranges)
• 不斷發展業界標準（evolving  industry standards)
• Blocks
• When your IP address has been blocked by an ISP or messaging organization. Blocks are less severe than bounces and do not result in permanent suppressions: subsequent sends to blocked email addresses are not automatically suppressed.
• 當你的IP位置被ISP或 messaging organization 【block】。
• 【Block】不像【bounce】那麼嚴重，不會導致永久禁止。
• 後續發送的已被block的信件也不會自動禁止。
• Spam Reports
• Whenever a recipient marks your email as spam and their mail server tells us about it.
• 收件人將您的email標記為垃圾郵件，他們的mail  server回傳告知。

筆記：自己依流程定義

• processed：已處理
• delivered：已送達
• open：開啟郵件
• click：開啟信件連結
• deferred：異常重送
• bounce：駁回重送'--rejected by the receiving mail server
• blocked：駁回
• dropped：被排除
• success：發送成功
• fail：發送失敗

正常流程：processed-->delivered(-->open開啟信件表示受件人有讀取到信)