The following article explains the events that are captured under MassMailer Mass Email Status related list. As you know MassMailer uses the SendGrid email server in the backend to send mass emails, so we do capture the events notified by the SendGrid server.


A request is an email sent and is reported in your SendGrid dashboard every time SendGrid servers get a “request” from the MassMailer application to send an email to one of your recipients.


This event fires when SendGrid receives an individual message and prepares it to be delivered. Think of this as the top of the funnel–unless it is dropped (see below), each message you push to SendGrid will create a processed event.


There are a number of reasons your email will not even be sent to a recipient for the delivery. This event informs your system when an email has been dropped. Further, it provides a reason for the drop, such as if we’ve found spam content (if the spam checker app is enabled) or we see the recipient has unsubscribed previously.


When an email cannot immediately be delivered, but it hasn’t been completely rejected, then the deferred event fires. Sometimes called a soft bounce, SendGrid will continue to try for 72 hours to deliver a deferred message.


If a server cannot or will not deliver a message, SendGrid fires a bounce event. Bounces often are caused by outdated or incorrectly entered email addresses. Many times you won’t know a bounced email address until it bounces. This event can help you ensure it doesn’t bounce again by removing it from your lists.


Blocked emails happen when your IP address has been added to a deny list or has been blocked by an ISP or messaging organization.

When your IP address has been added to a deny list or has been blocked by an ISP or messaging organization, the affected email shows up on this list. Typically it is possible to have your IP address removed from a block list, and some lists automatically do this after a period of time

Blocks are less permanent than Bounces. This is a list of refused messages that were either blocked by an ISP or deferred longer than 72 hours. In addition, SendGrid does not treat the blocks list as a suppression list - subsequent send to emails on this list will be sent like normal.


When an email has been accepted at the receiving server, the delivered event fires. This event does not guarantee that the email was placed in the recipient’s inbox. In fact, a delivered email is only the beginning of an opaque process. The remaining four events begin to give us hints about whether anyone will ever see this delivered email.

Clicks & Unique Clicks

The “Clicks” statistic represents the total number of times your users have clicked on the various links within your emails. “Unique clicks” represent the number of unique individuals that have clicked the links in your emails. So, if a certain customer clicks the same link more than once, it will only be reported once in the “unique clicks” count.

Opens & Unique Opens

The concept explained above regarding clicks also applies to opens. An important thing to keep in mind when evaluating numbers around opens is that many email clients often do not load images by default. Therefore, a customer could potentially open your email, read it, and even click a link, without an open being reported. This is obviously not ideal, but as we advance in our tracking mechanisms, we should be able to gain greater accuracy in instances such as this.


MassMailer lets you track the replies from your email recipients provided you set up the Reply Settings (previously called Inbound Parse) in MassMailer. 

Spam Report

Most internet service providers provide a feedback loop, sending specific spam complaints to email service providers. When SendGrid receives a notice, we fire a spam event, so that you can react appropriately–or at the very least, never send another email to that address.


One of the most important events fires when a recipient unsubscribes from your mailings. Reacting immediately to an unsubscribe by removing the email from your lists can pay long-term dividends in fewer spam reports and a higher engagement rate.

Group Unsubscribe

A group unsubscribe happens when a recipient indicates that they would like to opt-out from a specific type of email that you send via the Unsubscribe Groups link from within your email.