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#
- Sending everything at 9 a.m. in your own time zone.
- Blasting the full list in one minute and tripping provider throttles.
Fix and re-verify#
- Capture time zone at signup or infer from engagement.
- Analyze past click timestamps by segment.
- Use your platform's per-recipient optimization if available.
- Spread large sends over hours to avoid rate limiting.
Frequently asked questions#
What is the best time to send marketing emails?
There is no universal answer; mid-morning local time performs well for many B2B lists, but your own data beats benchmarks.