If a triggered activity is scheduled with a throttle rate of 0 messages per minute, email delivery is paused. However, the trigger itself continues to run on its schedule.

Each time the trigger runs, the system evaluates the targeting criteria and adds matching subscribers to the queue. Because no messages are being sent while the throttle is set to 0, the queued subscribers are not processed and the queue continues to grow over time.

What happens when a scheduled trigger is paused

1. The trigger runs at its scheduled interval.
2. Subscribers who meet the targeting criteria are added to the send queue.
3. Because the throttle rate is set to 0 messages per minute, no emails are delivered.
4. At the next trigger run, the same process occurs and additional subscribers may be added to the queue.

This repeats until the throttle rate is increased and the queue begins sending.

Once the throttle rate is set above 0, the system will begin processing and sending the queued messages at the configured rate.

How the queue grows over time

        Scheduled Trigger Runs
             (e.g. hourly)
                  │
                  ▼
     Subscribers Match Criteria
                  │
                  ▼
         Added to Send Queue
                  │
                  ▼
        Throttle = 0 messages/min
            ⏸ Sending Paused
                  │
                  ▼
          No Emails Are Sent
                  │
                  ▼
Next Trigger Run Adds More Subscribers
                  │
                  ▼
         Queue Continues Growing

Example of how the queue grows over time:

Trigger Run	Subscribers Added	Queue Total
Run 1	+120	120
Run 2	+120	240
Run 3	+120	360
Run 4	+120	480
...	...	...

(No sending occurs while throttle = 0)

When the throttle rate is set to 0 messages per minute, the trigger continues to run and queue subscribers, but no emails are sent. This causes the queue size to increase with each scheduled run until sending is resumed.

Need help clearing the queue?

If your queue has grown due to a paused throttle, contact Support to have the queued messages cleared. This helps prevent subscribers from receiving multiple copies of the same email once sending resumes.

If you believe this has occurred in your account, please reach out to Support and include the ID of the triggered activity so the team can review and clear the queue if needed.

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