Symptoms#
- Messages landing in spam despite previously good placement
- Bounces mentioning policy, authentication, or reputation
- Provider dashboards showing a drop in reputation or authentication pass rate
Diagnosis steps#
- Confirm the configuration is live: query DNS from an external resolver and check the sending platform's settings page.
- Send to a seed mailbox and read the full headers, especially Authentication-Results.
- Compare the domains in From, Return-Path, and DKIM d= for alignment.
- Check provider dashboards (Google Postmaster Tools, Microsoft SNDS) for reputation and error rates.
- Review recent changes: new vendors, DNS edits, list imports, volume spikes.
Likely causes#
- Using email address as the only identifier when users change it.
- No retry logic for failed webhook deliveries.
Fix and re-verify#
- List the events your product or store already emits.
- Send them to your ESP via webhook or native integration with a stable contact identifier.
- Deduplicate and validate payloads before they enter automations.
- Monitor for silent failures: a broken webhook stops journeys without errors.
Frequently asked questions#
Webhook vs API polling for email automation?
Webhooks are real-time and cheaper. Use polling only as a fallback reconciliation.