Some numbers you should know, when sending out e-mails:
When an e-mail template is used, the behaviour is monitored and the behaviour of all existing e-mails in our system.
There are such details like the opening and click numbers, or if the email was able to reach the recipient at all.
One useful information is the status code of the receiving mailserver:
For that we need to know how the way of the e-mail does look like: