Health is calculated from the spam rate over the last 14 days (health = 100 minus 2 × spam rate), so a drop means more warmup mail landed in spam inside the warming network. (A one-time drop on October 4, 2026 came from a calculation fix, not your mailboxes.) Diagnosis order. 1) Check whether the whole domain dropped or just one mailbox. 2) Check the domain's DNS status on the Domains page. 3) Check whether the domain has been blocklisted. 4) Confirm you haven't scaled cold sending above what the warming supports. 5) Review recent campaign content and lists. Each has a specific fix.
Diagnosis by cause
1. DNS problem on the domain
If the domain's nameservers were changed at your registrar, Winnr can no longer serve its DNS and authentication breaks.
- On the Domains page, a red status icon on an active domain means a DNS problem. Hover it to see what's wrong.
- For domains connected with manual DNS records, check that nobody changed or removed the records at your DNS provider.
- Fix per Monitor DNS health or DNS verification failing.
2. Blocklist listing
The domain got listed on Spamhaus, SURBL, or another blocklist.
- Confirm with the list operator's own lookup tool.
- If it's listed, see Domain on blocklist.
- Health won't recover while the listing stands, so plan to replace the domain.
3. Cold sending outpaced warming
You started sending real cold campaigns at high volume before the mailbox was ready. Providers noticed the spike and started filtering more aggressively.
- Check each mailbox's cold sending volume over the past 7 days in your sending tool.
- If it's high and the mailbox's health is under 80, you're pushing too hard.
- Scale back cold volume and let warming continue for another week.
4. Content or list problems
Recipients are marking your cold campaigns as spam, which pulls down the reputation your warmup mail relies on.
- On the Warming page, check whether the spam rate rose at the same time as health fell.
- Review your recent cold campaign content and targeting: spammy subject lines, weak targeting, or obvious bulk-send patterns.
- Fix the content and list, don't just wait. Reputation keeps sliding until you address the root cause.
5. Provider-side changes
Occasionally a major inbox provider tightens filtering for everyone. A drop across all your domains with no other explanation may be provider-driven, and it usually settles down on its own within a week or so.
Prevent future drops
- Keep an eye on the Domains page. A red status icon means a DNS problem to fix.
- Ramp cold sending gradually. Don't jump from warming volume to full cold volume overnight.
- Watch spam rate as a leading indicator. A rising spam rate predicts a health drop before it happens.
What's next
Frequently asked questions
How much drop is worrying?
A few points of movement is normal noise. A drop of 10 or more points means something changed. Falling out of the Good band (below 80) on several mailboxes at once is worth investigating right away.
What if all my mailboxes on a domain dropped at the same time?
That points to a domain-level cause, such as a blocklist listing or a DNS problem. Individual mailbox issues affect one mailbox, not the whole domain.
What if the drop is across all my domains?
Rarer, but possible. It usually means list quality or content in your cold campaigns has caused spam complaints across the board, or an inbox provider has tightened filtering. Contact support@winnr.app if you can't find a cause on your side.
My inbox rate looks fine but health dropped. Why?
A mailbox's health and inbox rate come from the same 14-day spam rate, so they always move together. If they seem not to, you're probably comparing a per-mailbox number with a chart or average that covers a different period or a different set of mailboxes. A genuine health drop always means spam placement in the last 14 days rose.
Many of my scores dropped on October 4, 2026 at the same moment. Why?
The calculation was corrected that day. It used to divide the last 14 days' spam by the last 45 days' sends, which made recent spam look up to several times smaller than it was. Both counts now cover the same 14 days. Nothing changed in your mailboxes; the score now shows recent spam at its real size. Use the steps below on any mailbox that is now under 80.
Health is fine, so why is my cold email landing in spam at Outlook or Yahoo?
The health score measures spam placement inside the warming network across all its providers, and that network can include very few Outlook.com, Hotmail or Yahoo addresses. A good score doesn't show how a specific provider treats your mail. Run a seed placement test to that provider (the How email warming works article explains how), then review volume, copy and list quality for that segment.
My health shows "--" or 0.
A mailbox that hasn't sent any warmup mail recently has no health score yet. Check that warming is running, not paused, and not showing Problem.
The mailbox's status is Problem, not just a low score.
That's a sign-in issue, not a reputation one. Warming can't log in to the mailbox, most often because its password was changed. On the Warming page, open the "..." menu on the mailbox's row and click Reconnect. It sends the current password to warming and restarts it, keeping its history.
Should I pause warming while diagnosing?
Only for domain-level issues where you suspect ongoing damage (a blocklist listing or a broken domain). For individual mailbox issues, keep warming running while you diagnose.