Reputation recovery
A step-by-step plan to bring a quarantined or low-placement mailbox back to healthy without making things worse.
Triage first
Before you start a recovery plan, decide whether the mailbox is worth recovering at all. Three questions:
- Is the mailbox tied to a person whose name needs to be on the email? If not, retire it and warm a new one.
- Has the domain been blocklisted at major receivers? Check tools like MXToolbox blacklist lookup, Talos, and Spamhaus. If yes, the recovery work is at the domain level too.
- Is the placement issue from this mailbox alone, or is it a domain-wide problem? Check placement on other mailboxes on the same domain.
Stop the bleeding
- Pause every campaign sending from the affected mailbox immediately.
- Remove the mailbox from active sender pools in your campaigns.
- If the mailbox is in the warmup pool, let the platform's auto-quarantine kick in (it likely already has).
- Do not "send a few test emails to gauge". Every additional send while reputation is poor is another data point in the wrong column.
Audit the basics
- SPF: single record? Under 10 DNS lookups? Includes every service that sends as you?
- DKIM: selector resolves? Key length ≥ 1024? Rotated within the last year?
- DMARC: exists? Aligned? Reporting address receives mail? Policy appropriate for your maturity?
- PTR: sending IP has a reverse DNS record that resolves back?
- Mailbox content: review the last 90 days of sent mail for any HTML-heavy, image-only, or link-bait messages.
Fix anything that's broken before you start the volume work. Recovery on a misconfigured domain is futile. See SPF, DKIM and DMARC for the details.
The recovery ramp
Treat the mailbox like a brand-new one. The ramp:
- Days 1–7: warmup only, capped at 5/day. No cold sends.
- Days 8–14: warmup at 10/day. Still no cold sends.
- Days 15–28: warmup at 15–25/day, ramp +1/day. Begin a very small "soft" cold sequence to highly engaged, low-risk recipients (warm replies are fine).
- Days 29–42: warmup at 30–40/day. Cold sequences capped at half the normal mailbox budget.
- Day 43+: evaluate. If placement is above 90% on a 20-message probe sample and complaint rate is below 0.03%, return the mailbox to the normal cold cap.
Send to your safest recipients first
The first cold sends after recovery should go to:
- Recipients who replied positively in the past 6 months.
- Contacts at organisations you have customer relationships with.
- Subscribers (newsletter, podcast, blog): addresses you've already had positive engagement from.
Reply-rich first sends rebuild engagement signal fast. Cold sends to brand-new contact lists during recovery are the easiest way to undo the work.
Content rules during recovery
- Plain text only.
- No tracking pixels.
- One link maximum, and only if necessary.
- Subject under 60 characters, no all-caps, no emojis.
- Different subject and opening line per recipient (not "Hi
{{first_name}}, just wanted to follow up" 1,000 times). - Personal signature with full name and a phone number you can be reached at.
When to give up and switch
If after 8 weeks of disciplined recovery the mailbox still hovers below 80% placement, the address has likely picked up reputation damage that won't reverse. Options:
- Retire the mailbox and create a new one on the same domain, then re-warm it from scratch.
- Move cold sending to a new sub-domain (e.g.
outreach2.acme.com) and start with fresh SPF/DKIM/DMARC. - If the whole domain is the problem, register a new sending sub-domain and warm it for 6 weeks before reusing.
Reputation recovery is mostly patience. The temptation is always to "test with a few sends". Resist it. A recovery plan that runs for 6 weeks of warmup-only beats one that gets impatient at week three and crashes back into quarantine.