Delivery

When email is not arriving, the cause is nearly always one of three things: the Send Integration, the domain's DNS, or what the bounces themselves are saying. This page is the order to check them in, and what each kind of bounce is telling you.

Instructions

1. Ask which send integration and sender domain are affected, and whether the issue is with a specific campaign or all sends.
2. Check the send integration status: Send Integrations > confirm status is "Active" and last test passed. If inactive, run a test to diagnose.
3. Check Delivery Events for recent activity: filter by the affected campaign and look at event types (Submitted, Sent, SoftBounced, HardBounced, Failed, Complained).
4. For bounces: identify soft (4xx, temporary) vs hard (5xx, permanent) bounces. Check specific bounce codes against the reference. Hard bounces require removing the address; soft bounces usually resolve on retry.
5. For domain-wide failures: verify authentication DNS records — Sender Domains > confirm SPF, DKIM, DMARC all show "Verified". Check if records changed or expired recently.
6. For spam folder issues: check sender reputation via ESP dashboard, review content for spam triggers, confirm visible unsubscribe link, verify both HTML and plain text versions exist.
7. If the issue persists, check the ESP's status page for outages, or suggest setting up a Bounce Rule (Delivery Events > Bounce Rules) to auto-suppress problem addresses.

Related pages

• Email Bounce Codes Reference — covers Quick Diagnostic Flowchart, Soft Bounces (Temporary - 4xx), Hard Bounces (Permanent - 5xx), Authentication-Related