A bounce is not just a failed send. It is a signal about your list, your verification, and your sender reputation. Hard bounces that keep firing from the same sequence will eventually get the whole domain filtered.
A clear handling routine keeps the damage contained and tells you where the bad data came from.
The routine has three parts. Classify the bounce, suppress the address, then trace it back to the source. Skipping the last part means the same bad list gets imported again next month.
What a hard bounce actually means
A hard bounce means the receiving server has permanently rejected the address. The mailbox does not exist, the domain does not exist, or the server refuses all mail from you. Continuing to send to that address repeats the failure and adds negative signals.
Treat a hard bounce as a removal, not a retry. The address should be suppressed across every sequence, not only the one that hit it.
Separate hard from soft bounces
Soft bounces are temporary. A full mailbox, a greylisting delay, or a short server outage can produce one, and a later retry may succeed. Your sending tool should retry soft bounces a small number of times before treating them as hard.
Review the bounce code rather than the label alone. Some tools categorize by a generic reason, and a code that looks soft may indicate a permanent failure at the domain level.
Keep the two categories in separate reports. Mixing them hides a real deliverability problem behind what looks like normal temporary noise.
Suppress the address everywhere
Once an address is confirmed hard, add it to a global suppression list, not just the current campaign. The next sequence, the next tool, and the next import must all respect that list.
Check that your sending tool and your CRM share the suppression state. A contact marked bad in the outbound tool but still active in the CRM will be emailed again by a future campaign.
Export the suppression list on a schedule and keep it with your list management files. It is a small file that prevents a large problem.
The Instantly help center documents how its accounts handle bounce detection and lead status. Confirm the current behavior before you rely on an automatic rule.
Trace the bounce back to the source
Every bounced address should be traceable to the list or import it came from. Tag records by source when you import them so you can answer a simple question: which source produced the most bounces?
A source with a high bounce rate is either old, scraped, or never verified. Flag it and stop using it until it is cleaned.
If one source dominates the bounces, the fix is upstream. Cleaning the sequence after the fact treats the symptom, not the cause.
Check the sending tool's own handling
Confirm that your tool suppresses hard bounces automatically and that the setting is on. Some tools require you to enable suppression or to set a threshold before they stop a lead.
Review what happens to a bounced lead in the sequence. It should leave the sequence, not sit in a paused state that a later run resumes.
Test the behavior with a known bad address on an internal test sequence. A five minute test proves the rule works before real volume is affected.
Review domain level blocks
If many addresses at one domain bounce at once, the domain is blocking you rather than the mailbox being invalid. That is a reputation issue, and continuing to send makes it worse.
Note the domain, pause sends to it, and check whether your messages are being filtered. Sometimes a single bad send to a large domain affects every later message to that company.
Do not treat a domain block as a bad address. Suppressing the whole domain may be right temporarily, but the underlying reputation problem still needs attention.
Report bounce rate by campaign and source
Track bounce rate as a percentage, not a raw count, because volume changes between campaigns. A useful report breaks the rate down by list source and by sequence.
Set a threshold for action, such as pausing a sequence when the hard bounce rate crosses a small percentage. The threshold turns a metric into a decision.
Share the report with whoever owns list sourcing. Bounce rate is their feedback loop as much as yours.
Keep the suppression list clean
Merge duplicate entries and remove placeholder addresses so the list stays usable. Store it in one canonical place and let the tools read from it.
Review the list after every large import to confirm no suppressed address slipped back in. Reintroducing a suppressed address is one of the most common and most avoidable outbound mistakes.
Set a bounce threshold you can act on
Decide in advance what bounce rate should trigger a pause. A hard bounce rate above a small percentage on a sequence is enough reason to stop and investigate.
Write the threshold where the person running the sequence can see it, and give that person authority to pause without waiting for approval. A fast pause protects the domain.
Review the threshold quarterly as your list sources change. A rate that was normal for a scraped list is not normal for a verified one.
Handling bounces is rule based work that a trained operator can run every day from a documented threshold. To have it covered, review our outbound sequencing service, or request a consultation with your current bounce reports.
