salesforce email log
由于网络是不可靠的，所以是否发送除了逻辑还有可能是邮箱问题
reference
https://fairsail.my.site.com/sagepeoplecustomercommunity/s/article/How-To-Run-And-Check-Email-Logs#:~:text=R - Reception The email was successfully received.,Salesforce will retry delivery over a 24-hour period.