Missing Email Sends Within Twilio Marketing Campaigns

What is email suppression?

A suppression is the action the sender takes by no longer sending to an email address when a recipient has opted out of an email list or when the recipient’s email server or provider has rejected emails sent to that address. Within our system, suppressed emails are those listed under Global Unsubscribe, Group Unsubscribe, Bounces, Invalid emails, and Spam Reports.

If an email is listed on any of the above, the emails will be dropped prior to the send being attempted.  If sending via SMTP or API, a drop event is visible for this within your Activity Feed. However, for Marketing Campaigns, emails are not attempted if on any list above so you will not see a drop event thus the name “Silent Drop.”  This is most visible when a campaign is sent to less recipients than requested.

Emails dropped in SMTP/API sending will still count as an email credit, Marketing Campaign “Silent Drops” do not count towards credits


Does this affect all sends or only specific ones?

Any email sent via the Twilio Sendgrid platform must respect listed account suppressions.  This includes SMTP sends, API sends, and emails sent via Marketing Campaigns.

Customers can add specific email addresses to an allow list to never be suppressed if they so choose.  We caution the use of the allow list as not suppressing a customer who is requesting suppression can impact reputation and violates the Twilio Sendgrid terms of service.

Customers managing their suppressions outside of Twilio Sendgrid are excluded as long as no emails are listed in the suppression groups.


How to avoid Silent Drops?

Silent drops can be avoided by proper contact management and ensuring your lists are kept up to date.  This includes frequently cleaning your suppression lists and ensuring any customers listed within your suppression lists are not also within contacts. You can also add any specific email addresses to your Address Allow List.


Steps to check if your send is impacted by “Silent Drops”:

  1. Checking for “Silent Drops” starts with exporting the list of recipients you were looking to send a campaign to. This can be done by going to Marketing > Contacts > [Your list used in the campaign] > Export (Located in three dot menu button right of the list)
  2. You will now want to export your suppression lists. You will want to start with the unsubscribe group selected within your campaign (this can be a group or global) as well as the bounce list. This can be done by hitting the gear icon in each respective section and selecting export.
  3. You will then want to use a tool such as Microsoft Excel to compare the lists and find the overlapping contacts.  The overlap are those that were dropped due to being suppressed. (Apart from any on the address allow list)


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