Managing email campaign dispatch interruptions

Current version: 10.4

When an email campaign is dispatched, it moves through a number of states (Draft, Queuing, Sending, and Sent). If an error occurs during dispatch and the IIS server is interrupted, the email campaign is not moved to the Sent state. Instead it is moved to the Paused state and you must resume the email campaign manually.


There is no default functionality to automatically resume paused dispatches. For an explanation of how to create a customization, see the "Automatically resuming paused email campaigns" blog post.

When using a Dedicated Dispatch Server (DDS), however, the DDS server continues dispatching messages without the Content Management (CM) server. The campaign state is set to Paused and you must resume it manually. If you do not want to manually resume the email campaign, you can implement a Sitecore job that verifies the paused campaigns and resumes them. When an email campaign is interrupted and not all email messages sent, there might be a few remaining items in the dispatch queue. These are processed when you resume sending the email messages.

To better understand what happens when an email campaign dispatch is interrupted, consider the following scenario.


This scenario assumes that:

  • NumberThreads = 10  in both DDS and CM

  • DispatchBatchSize = 100 in both DDS and CM

  • Recipients List Size = 10,000 contacts

  1. The Email Experience Manager (EXM) starts sending email messages and both the CM and DDS each pick up 1,000 items (10*100) from the dispatch queue and start processing them.

    Diagram illustrating how EXM processes emails.
  2. While the CM processes the 1,000 items that it has picked up, the server stops working and the dispatch is interrupted. Out of the 1,000 items:

    • 200 are processed

    • 800 are marked as In progress

    The DDS continues processing the remaining 8,000 items and when it finishes, 8,200 emails are dispatched and 800 are marked in progress.

    At this point, EXM considers the campaign to be paused because there are 800 items In progress that are not being processed. When the campaign resumes, these 800 items are processed and the campaign state is changed to Sent.

    Diagram of how EXM handles dispatches.

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