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#
- Warming with fake engagement networks that providers now detect and penalize.
- Warming the IP but sending from an unauthenticated subdomain.
- Treating warm-up as one-time; reputation decays after inactivity.
Fix and re-verify#
- Start with 20 to 50 messages per day per mailbox to your most engaged, opt-in contacts.
- Double volume every 2 to 3 days while complaint and bounce rates stay clean.
- Prioritize recipients likely to reply or click; positive engagement accelerates trust.
- Monitor Postmaster Tools daily and pause the ramp if reputation drops.
- Reach target volume over 4 to 6 weeks for a cold domain; faster if you have an established parent domain.
Frequently asked questions#
How long does email warm-up take?
Two to six weeks depending on target volume and whether the domain is brand new.
Do I need to warm up a shared IP?
The IP is already warm, but your domain is not. Domain warm-up still applies.