Getting started
Initial deliverability checks
Identify the failing stage, preserve the evidence and choose the next investigation.
Start with one affected message and its actual sending route. Use these checks to decide which evidence to collect next.
Collect the evidence
- Record the UTC timestamp, sending system, message or queue ID, destination provider and complete SMTP reply. Keep the original message headers if a recipient received it.
- Separate failed submission, deferred delivery, permanent rejection and spam placement. A successful SMTP handoff establishes acceptance, not an inbox result.
- Identify the connecting IP, envelope sender domain, visible From domain and DKIM signing domain. Use the message and logs rather than the account display name.
Choose the next check
| Observed problem | Next step |
|---|---|
| Authentication failure | SPF, DKIM and DMARC alignment |
| PTR or hostname error | Reverse and forward DNS |
| Temporary deferrals | Incident playbook and queue handling |
| Accepted but unwanted | Consent, complaints and suppression |
Change one confirmed cause
SendPoint recommendation: record the previous setting, owner and rollback before editing DNS or sending policy. Verify the change using a new message through the same production route. Keep the original failure as a comparison, and expand the investigation when the new result contradicts the initial explanation.