Instantly Health Score Dropped After a Bad List? What the Score Measures and How to Recover the Inboxes

Pause campaign sending on the affected inboxes, keep warmup running, fix anything Test Domain Setup flags, and verify the remaining leads before you resume. The health score tells you how warmup mail is landing; after a bad list, it's a lagging and partial signal, not the whole picture.

Sources, read 2 November 2026: Instantly's help articles Warmup Health Score, When Your Email Account Is Ready for Campaigns and High Bounce Auto-Pause Feature.

What the number is, and isn't

Item	Instantly's definition
Health score	Warmup emails in inbox ÷ warmup emails sent × 100
Window	Rolling last 7 days
Target	Above 90%
Campaign-ready	2+ weeks warmup (3 for AirMail) and score above 90%
Score of 0	New account before first warmup day, or no warmup sent in 7 days
Scope	Warmup placement only, not campaign placement

That last row matters after a bad list. Bounces and spam-folder placement from a campaign hurt the sending domain and mailbox with Gmail and Microsoft, but the score is calculated only from warmup mail. It can stay high for days while campaigns land badly, then fall later. Read it alongside your campaign bounce rate and reply rate, not instead of them.

Step by step

1. Stop campaign sends from the affected inboxes. If High Bounce Auto-Pause already stopped the campaign (over 5% bounces after at least 200 sends, on by default), leave it paused until the list is fixed.
2. Keep warmup on. Pausing warmup too resets the score to 0 after 7 days and removes the engagement that helps recovery.
3. Run Test Domain Setup on the dashboard and fix any missing MX, SPF, DKIM or DMARC record. Instantly sets DNS for DFY, AirMail and pre-warmed accounts.
4. Use Instantly's recommended warmup settings: increase per day 1, daily warmup limit 10, reply rate 30%, slow warmup not disabled.
5. Export the unsent and bounced leads. The Instantly leads to email list tool turns the export into a clean list, then verify it on the verify page and remove invalid results before anything is re-uploaded.
6. Check placement on real campaign copy with a seed test; the health score can't tell you this.
7. Resume slowly, at lower daily volume per inbox, once the score is back above 90% and the list is clean.

Honest limits

A clean list stops new damage; it doesn't undo what's already happened, and recovery takes as long as the providers take to see better mail. Verification also can't confirm every address: catch-all domains accept anything, and Microsoft-hosted mailboxes often don't give a clear answer, so a share of B2B results comes back risky or unknown. Send those last, from your healthiest inboxes, or leave them out. If you're deciding whether to use Instantly's built-in checks or a separate one, see verifying Instantly leads with the native integration, and for the bounce side, keeping Instantly's bounce rate under control.

Where SimpleVerifier fits

Verify the remaining leads on the verify page before you resume. The first 100 checks are free with a Google sign-in. Pro is $39 a month with the first 100,000 checks a month at full speed, then slower, never cut off. See pricing.