Prospects failed with 'stuck in processing loop' error
If you see prospects marked as 'Failed' with the error 'Failed: stuck in processing loop after 3+ recovery cycles', this means the system tried to send an email to the prospect three times but could not complete the send each time.
Why this happens:
- Your mailbox hit its daily sending limit — If your campaign has more prospects scheduled to send than your mailbox can handle in a day, some send jobs get stuck waiting for capacity. After 3 retries without successful delivery, the prospect is marked as failed.
- Only one mailbox assigned — With a single mailbox and a low daily limit (e.g., 30/day), the system cannot process high volumes. Jobs compete for limited send slots.
- Sending window too narrow — If your sending window is short (e.g., 2 hours) and many sends are scheduled, some may not get processed in time.
How to fix:
- Add more mailboxes to your campaign — Go to Campaign Settings and assign 3-5 mailboxes. Use mailbox rotation (round-robin) to distribute load.
- Reduce daily campaign volume — Lower your per-campaign daily send limit to match your available mailbox capacity.
- Widen your sending window — A wider sending window (e.g., 8 AM to 6 PM instead of 9-12) gives more time to process all sends.
- Check mailbox health — Ensure all assigned mailboxes are connected and not in error state.
Recovering failed prospects:
Failed prospects can be re-enrolled in a new campaign. Export or note the failed prospect emails from your campaign detail page, fix the capacity issue (add mailboxes, reduce volume), and create a new campaign targeting those prospects.
Prevention:
As a rule of thumb, your total daily mailbox capacity (number of mailboxes × daily limit per mailbox) should be at least 2x your campaign's daily send target. This ensures there is always available capacity even during peak scheduling.