Lowering Bounce Rate in lemlist Campaigns: A Practical Guide

To lower bounce rate in lemlist, verify leads before they enter a campaign, send only to Deliverable addresses, run Risky ones in a separate campaign, keep daily volume within lemlist's own caps, and pause at 5% yourself. lemlist's automatic safety net is set far higher: alerts at 10% and an auto-pause at 50%.

Those numbers come from lemlist's own help centre, read on 1 October 2026, and the distance between them is the main thing to plan around.

lemlist's thresholds, side by side

lemlist advises stopping at 5%, but its automation only steps in at 10% and 50%. Both figures are on the same page, its guide to reducing email bounces:

What	Figure	lemlist's wording
Advice	5%	"Pause campaigns if the bounce rate is high", triggered when "bounce rate exceeds 5%"
Alert	10%	"bounce rate alerts are triggered at 10%"
Auto-pause	50%, after 100 leads contacted	"campaigns are automatically paused at 50% if at least 100 leads have been contacted"
Healthy target	under 3%	"Maintaining a low bounce rate (under 3%)"

The 50% auto-pause is a catastrophe brake. By the time half of the first hundred emails have bounced, the sending domain has already taken the damage. The articles we read describe the 10% alert and 50% pause and do not mention a way to lower them, so the practical stop rule in lemlist is one you enforce by watching the campaign.

For comparison, Instantly's documented default is a 5% pause after 200 sends (details), and Smartlead lets you set the threshold yourself (details).

Set your own stop rule

Decide before launch what bounce rate makes you pause, and check it daily for the first week. lemlist's own figures give you a sensible ladder:

1. Under 3%: carry on, lemlist's "low bounce rate" target.
2. Above 3%: hold volume, do not scale up. lemlist says "a bounce rate above 3% is one of the criteria that says hold your volume at the low end rather than moving up."
3. Above 5%: pause the campaign and clean the list, as lemlist advises.

Where to look: open the campaign, go to Overview, and scroll to Negative signal stats, which shows Bounced, Unsubscribed and Not interested (guide). You can also filter the campaign's leads by the Bounced status to see exactly who bounced.

Use lemlist's deliverability statuses properly

lemlist marks each verified email as Deliverable, Risky or Undeliverable, and only the first is safe for a cold campaign. Hover over the verification icon next to an address to see its status. lemlist's deliverability statuses guide defines them:

Status	Meaning	What to do
Deliverable	"The recipient's email provider confirmed that the email address is valid and active"	Send
Risky: accept all	The inbox "accepts all incoming emails, regardless of whether the address actually exists"	Separate campaign, or skip
Risky: full inbox	"The recipient's inbox is full and cannot receive new messages"	Retry in a few weeks
Risky: disposable	A temporary or throwaway address	Skip
Undeliverable	"Either incorrectly formatted or does not exist"	Remove before launch

lemlist's own guidance on risky leads is to send to accept-all addresses only "if your domain reputation is strong and bounce rate is low (<3%)", and to "skip risky addresses entirely" if bounce rate is already above 5% or the domain is new. It also suggests running accept-all addresses "in a separate campaign" and monitoring them closely.

That separation is the single most useful habit. Accept-all is lemlist's name for a catch-all domain: the server says yes to every address, so no verification can confirm the mailbox. Mixing those leads into your main campaign means you cannot tell whether a rising bounce rate comes from bad data or from the catch-all segment.

To remove undeliverable leads in bulk: in the campaign's leads list, filter Status to Undeliverable, select all, and click Remove from campaign.

Verify before leads enter the campaign

Statuses appear only after enrichment, so leads uploaded straight into a campaign may have none. lemlist's statuses guide says that if you don't see a status, "email verification not enabled, or leads not enriched yet", and the fix is to select leads and click Enrich.

You have three routes:

• lemlist's own enrichment, which verifies as part of finding and enriching leads.
• The Bouncer integration. lemlist documents a Bouncer connection that verifies a campaign's leads through the API and can remove undeliverable addresses with one click. The guide warns that this removal is permanent: "Removed leads deleted from campaign. Cannot undo. Export list first if you want backup."
• Verify the CSV before import with any verifier, and import only what you plan to send.

Whichever you use, clean the file first: lower-case, trim and deduplicate the email column so you do not verify or email the same person twice. The formulas are in our Excel and Google Sheets guides.

On timing, lemlist's statuses guide says to re-verify "if your email list is more than 6 months old", and its Bouncer guide says lists "older than 3-6 months" should be re-verified. We would use the shorter end for B2B lists, where people change jobs continually.

Keep volume inside lemlist's caps

A clean list sent too fast from a new mailbox still bounces, as receiving servers throttle and reject unfamiliar senders. lemlist's bounce guide lists "high email volume or sudden spikes" among the causes of soft bounces, and gives specific limits:

Situation	lemlist's guidance
Warm-up before any cold sending	"About 40 days of ramp-up at +1/day, then 14 days holding at target, with no campaigns under a warm-up score of 90"
New mailbox out of warm-up	"30–40 emails/day through lemlist. Open at 30"
Total per email provider	"lemlist + lemwarm + manual replies — under 70/day"
Domain under one month old	"Under 100/day across every mailbox on it combined"
Inbox rotation	Mailboxes "on the same provider share one reputation budget rather than each getting a fresh one"

The last row matters if you plan to scale by adding mailboxes on one domain. More inboxes do not mean proportionally more safe volume.

Know what happens to a lead after it bounces

In email-only campaigns a bounce stops that lead's email steps; in multichannel campaigns other channels carry on. lemlist's bounce guide: "For email-only campaigns, a bounce immediately ends subsequent email steps for the affected lead. However, in multichannel campaigns, while email steps fail post-bounce, other channels like LinkedIn or calls continue unaffected."

That is useful: a bounced lead in a multichannel sequence can still be reached on LinkedIn. It also means the lead stays "active" in your campaign view, so check the Bounced filter rather than assuming the sequence has dropped them.

After each campaign, export the bounced leads and remove them from your master lead file, so the next campaign does not import them again.

Read the bounce reasons before re-verifying

Some bounces are a bad address; others are your setup. lemlist lists both kinds of hard bounce: "invalid or non-existent email address" and "blocks due to provider-specific reputation-based evaluations". Re-verifying a list will not fix the second.

If bounces mention authentication, policy or reputation, check SPF, DKIM and DMARC on the sending domain (the deliverability audit does all three) and look at blocklists before blaming the data. lemlist's own checklist suggests confirming all three DNS records and monitoring blacklists weekly.

A pre-launch checklist for lemlist

1. Lead file cleaned and deduplicated.
2. Every lead enriched or verified, with a status showing.
3. Undeliverable leads removed; disposable leads skipped.
4. Accept-all leads in a separate campaign, or left out if the domain is new.
5. Mailbox warmed, starting at 30 a day; provider total under 70 a day.
6. SPF, DKIM and DMARC passing.
7. Your own stop rule written down: hold above 3%, pause above 5%.
8. Someone checking Negative signal stats daily during week one.

The takeaway

lemlist gives good advice, under 3% healthy and pause above 5%, and then sets its automatic alert at 10% and its auto-pause at 50%. Close that gap yourself. Verify and enrich before launch, send to Deliverable addresses, keep accept-all leads in their own campaign, stay within lemlist's volume caps, and pause manually at 5% while you read the bounce reasons.