Apollo Sequence Paused by Bounce Guard: How to Clean the List and Reactivate

What Apollo's help center says

Apollo's knowledge base article Report on Sequences describes the Health tab: it shows a sequence's recent bounce rate and recommended actions, and Apollo compares that rate with the thresholds your team set in Bounce guard. In Apollo's words, "Your team's Bounce guard settings determine when Apollo flags or pauses a sequence."

To bring a paused sequence back, Apollo says to open its Health tab, complete a cleanup action such as enriching contacts or removing bounced ones, and click Activate; Apollo then resets the bounce evaluation. Apollo's Troubleshoot Bounced Emails article covers individual bounced contacts. (Apollo's help center blocked automated reads when we checked on 8 November 2026, so open the articles for the current wording and your team's actual thresholds.)

Bounce guard thresholds are per team, so ask whoever admins your Apollo workspace what they're set to rather than relying on a number from a blog.

Step 1: check the bounces are list bounces

Open a handful of bounced emails and read the reply:

• 550 5.1.1, "user unknown", "recipient not found", "address rejected": the mailbox doesn't exist. List problem.
• "blocked", "SPF", "DKIM", "DMARC", "reputation", "rate limited": your mailbox or domain. Sending problem.

If it's mostly the second kind, fix the setup before anything else. The cold email domain checker checks SPF, DKIM, DMARC and MX in one go, and Google Workspace suspended for cold email covers the worst case.

Step 2: export what hasn't been sent

From the sequence, filter to contacts that are still active or not yet contacted and export them to CSV. The Apollo contacts to email list tool pulls the email column and Apollo's email status out of the export, so you can see how many rows Apollo marked verified, unverified, catch-all or unavailable, and which already show as bounced.

Step 3: verify every row, whatever Apollo's status says

Upload the CSV to the verify page, or use the Apollo email verifier. Each address gets a live SMTP mailbox check today:

Result	Action in Apollo
Valid	Keep in the sequence
Risky (catch-all)	Remove from this sequence; add to a smaller catch-all sequence, best grades first
Risky (role, disposable, mailbox full)	Remove for cold outreach
Invalid	Remove and mark as bounced or do-not-contact
Unknown	Hold; re-check tomorrow

Catch-all domains are the reason "verified" contacts bounce. The receiving server accepts any address during a check, so nobody can confirm the mailbox from outside. SimpleVerifier never labels a catch-all valid; it reports it risky with a grade and the reason (catch-all scoring). Our Apollo verified emails bounce post explains the status labels in more depth.

Step 4: clean up in Apollo and reactivate

1. Remove the invalid and risky contacts from the paused sequence.
2. Remove already-bounced contacts (this counts as Apollo's cleanup action).
3. Click Activate on the Health tab.
4. Send the catch-all sequence separately, a few hundred at most, and stop it if hard bounces in it pass 2%.

Step 5: stop it happening on the next list

• Verify every Apollo export on the day you load it into a sequence, not the day you saved the list. See verify an Apollo export.
• Keep sequences small enough that one stale segment can't sink a mailbox. Apollo's sending limits article suggests linking more mailboxes rather than raising one mailbox's daily limit.
• Re-verify contacts older than a month before reusing them: re-verify leads older than 30 days.

Mailbox providers don't publish a bounce number, but they do publish complaint limits: Google's sender guidelines say to keep your spam rate below 0.1% and never reach 0.3%. Stale lists drive both bounces and complaints, so the same pre-send check helps with each.

What it costs to verify every Apollo export

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, 5 seats, priority lane.
• Agency, $249 a month: the first 750,000 checks a month at full speed, 15 seats, client workspaces and reports.

*Pro fair use: the first 100,000 checks a month at full speed, then slower, never cut off. See pricing. Check your list free: the first 100 checks are free with a Google sign-in, no card.

More reading: Apollo export to sequencer, catch-all leads in sequences, what to do after a high bounce rate, and our verify your list before cold email guide.