Woodpecker Bounce Shield: Why Your Campaign Paused and How to Stay Under 2%

What Woodpecker says Bounce Shield does

From Woodpecker's email verification feature page, read on 8 November 2026:

• Bounce Shield "pauses a campaign at 2% by default".
• You can "set your own threshold".
• The campaign list flags the pause, and you restart the campaign.

Woodpecker's help article How to lower my bounce rate? recommends "keeping your Bounce rate below 5% per campaign" and lists the causes to check: SPF and DKIM, blocklists, invalid or deactivated addresses, and new domains. It says that if your domain is younger than 3 months, you should stop sending and warm it up first.

Don't confuse Bounce Shield with Adaptive Sending. Woodpecker's Adaptive Sending article describes a feature that cuts volume when you approach your email provider's sending limits. It says plainly that it doesn't prevent bounces.

Step 1: find out what kind of bounces paused you

Open the bounced prospects and read the reply text, not just the count.

Bounce text contains	Likely cause	Fix
550 5.1.1, "user unknown", "does not exist", "recipient not found"	Dead mailbox on your list	Remove it; verify the rest
"domain not found", 5.1.2, no MX	Dead company domain	Remove every row at that domain
"SPF", "DKIM", "DMARC", "unauthenticated"	Your DNS	Fix records, then resume
"blocked", "reputation", "listed", "spamhaus"	Your IP or domain reputation	Stop, check blocklists, slow down
"mailbox full", "quota"	Temporary on their side	Retry later, drop if it repeats

Paste a few into the bounce message analyzer if the wording is unclear. If most bounces are authentication or reputation ones, a cleaner list won't help; check the domain with the cold email domain checker first.

Step 2: understand what Woodpecker's own check covers

The same Woodpecker page says it checks each address with Bouncer "right before the email goes out", marks addresses that don't exist as INVALID and skips them, and that the check is "not bulletproof". Catch-all addresses get one of four campaign settings:

• Only verify: catch-alls are checked and sent nothing.
• Maximum: sends only to catch-alls considered safe.
• Balanced (the default): sends to deliverable and risky catch-alls.
• None: sends to all catch-alls, including undeliverable ones.

So on default settings, risky catch-all addresses still go out in the same campaign as your confirmed ones. Catch-alls are where most surprise bounces on a "verified" list come from, because the server accepts every address during the check and rejects later. If you send big lists, switch the campaign to Maximum or Only verify, or split catch-alls out before import.

Step 3: verify the list before it reaches Woodpecker

1. Export the prospects you plan to send to as CSV. The Woodpecker prospects to email list tool pulls a clean email column out of a Woodpecker export.
2. Remove duplicates with remove duplicate emails and cap contacts per company with limit contacts per company.
3. Upload the file to the verify page. Every address gets a live SMTP mailbox check and comes back valid, risky or invalid, with the reason.
4. Import only valid rows into the main campaign.
5. Put risky catch-all rows in a second, smaller campaign, best grades first. SimpleVerifier never calls a catch-all valid; it grades them so you can choose (how grading works).
6. Add invalid rows to your Woodpecker blacklist so a later import can't bring them back.

Step 4: resume safely

• Resume only after the cause is fixed. If the bounces were list bounces, remove the bounced rows and re-verify the rest of the unsent prospects; the export may be weeks old.
• Watch the first day closely. One bad segment can trip the threshold again.
• If you changed DNS, Woodpecker's help article says you can resume straight away. After a reputation problem it says you may need to wait "a few weeks or even months".

Why 2% matters beyond Woodpecker

Mailbox providers don't publish a bounce threshold. What they publish is complaint rates: Google's email sender guidelines say to keep the spam rate reported in Postmaster Tools below 0.1% and never reach 0.3%, and Yahoo's sender best practices also set 0.3% as the ceiling. Bounces to addresses that don't exist are an early sign of a stale or bought list, which is the kind of list that also draws complaints. A 2% pause line keeps you well clear of that. See bounce rate thresholds by platform for how other tools compare.

What checking a big list costs

SimpleVerifier's monthly plans:

• Starter, $9 a month: 2,500 checks.
• Pro, $39 a month: Unlimited email verification.*
• Business, $99 a month: the first 300,000 checks a month at full speed, a priority lane and 5 seats.
• Agency, $249 a month: the first 750,000 checks a month at full speed, 15 seats, client workspaces and branded client reports.

*Pro fair use: the first 100,000 checks a month at full speed, then slower, never cut off. Business and Agency also keep running past their volume in the slower lane. Full details on pricing. Check your list free first: the first 100 checks are free with a Google sign-in.

More reading: preparing a list for Reply.io, Woodpecker or Saleshandy, catch-all leads in sequences, pause a campaign after a bounce spike, and our verify your list before cold email guide.