How to Classify Cold Email Replies and Suppress the Bounces

To classify cold email replies and suppress the bounces, export the campaign's replies, sort them into labels with the free reply classifier, pull every Bounce and Unsubscribe out of the list, add those addresses to your sender's block list and re-verify everyone left. The order matters. Suppress first, so the same address is never mailed again from any campaign.

This guide is for people who already ran a campaign and have replies and bounces in an export. Templates for the same job live on the bounce recovery template page.

Step 1: pause the campaign

If bounces are rising, pause the campaign in Instantly or Smartlead before you do anything else. Every extra send to a bad list costs reputation. Instantly bounce rate and Smartlead bounce rate explain what the numbers mean for each tool.

Step 2: export the replies

Export the replies from your sequencer as a CSV. The classifier looks for a column named reply, body, message, text, content, snippet or response. It looks for the lead's address in a column such as email, from or lead. You can also paste replies as text, separated by blank lines or by a line of three or more dashes.

Step 3: run the reply classifier

Open the AI email reply classifier and paste or upload the replies. It works on 25 rows signed out and 200 signed in. Each reply gets one of these labels:

• Interested
• Not now
• Not interested
• Out of office
• Wrong person
• Unsubscribe
• Bounce

AI mode on this tool says coming soon, so today it uses fixed keyword rules. A reply the rules cannot place is labeled Needs review. Read every one of those yourself. Keyword rules miss tone, sarcasm and mixed messages, and a missed Interested reply is worth more than a wrongly labeled Out of office.

Step 4: act on each label

Label	What to do
Interested	Answer by hand today.
Not now	Note a date and follow up later, if the lead asked for it.
Not interested	Stop the sequence. Do not add to a new campaign.
Out of office	Wait, then re-send or let the sequence continue.
Wrong person	Stop. Ask for a referral if it is natural.
Unsubscribe	Suppress at once and never mail again.
Bounce	Go to the next step.

Honoring an unsubscribe is both a legal and a reputation matter, so treat that label as final.

Step 5: sort the bounces

Open Bounce Doctor and paste the bounce messages or a bounce export. It runs in your browser and nothing you paste is uploaded. It sorts addresses into four groups:

• Remove: the mailbox does not exist or the address is dead.
• Retry: a temporary problem such as a full mailbox.
• Sender problem: the rejection is about you, not the address.
• Unclear: read these by hand.

The sender group matters most. Codes that start with 5.7 are about your domain, IP or content. Check SPF, DKIM and DMARC before blaming the list. Verifying addresses will not fix an authentication problem.

Step 6: suppress

Copy the remove group and the Unsubscribe replies. Add them to your sender's block list, or to the global block list so no campaign can mail them again. Platform steps are in suppression list from Smartlead and suppression list from Lemlist or Instantly.

Step 7: re-verify the rest

Verify every remaining lead in the campaign. You have two routes:

• For Instantly and Smartlead, connect your key and verify the campaign directly. Tagging is the default and removal or blocking is opt-in. Verify Smartlead campaign leads and verify Instantly leads without exporting show how.
• Or export the leads as a CSV and upload it on the verify page. It works for any sender. The first 100 checks are free with a Google sign-in, no card.

Read the results. send means the mail server confirmed the mailbox. send_with_care covers catch-all domains, role inboxes and providers that hide status. do_not_send is a hard no. If you see many send_with_care rows, the catch-all study explains why: 39.1% of 4,943 sampled business domains accepted a made-up address.

Step 8: restart small

Restart with only the send leads, at a lower daily volume. Watch the bounce rate for a few days before you raise it. Pause risky leads rather than deleting them until you know why they failed.

Where your judgment still matters

Classification by rules is a first pass. Read Needs review rows and any reply that mentions a person leaving, a legal threat or a complaint. Re-verifying removes addresses that will bounce. It does not fix authentication, sending volume or content, which are the other common causes of bounces.

If you want a list-cleaning run before the next campaign, see clean a lead list before a campaign. To protect an inbox after a bad send, read Smartlead inboxes after a bad list.

Keep a log

Write down, for each campaign, how many replies landed in each label and how many addresses you suppressed. After two or three campaigns the numbers show you where the problem is. A high Bounce count points at the list. A high Wrong person count points at your targeting. A high Unsubscribe count points at your message or your volume.

Frequently asked questions

Does the classifier use AI? Not yet. It says AI mode is coming soon and uses fixed rules.

How many replies can I check? 25 signed out, 200 signed in.

Does Bounce Doctor upload my bounces? No. It runs in your browser.