[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
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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)