How bounces are handled
What CarcMail does when an email bounces — and how to keep your bounce rate low to protect sender reputation.
A bounce rate above 5% is a warning sign. Above 10% can cause email providers to start throttling or blocking your inbox. CarcMail monitors your bounce rate automatically and will pause your campaigns if it gets too high.
Overview
A bounce happens when an email you send cannot be delivered and the receiving mail server returns an error message. There are two types of bounces, and they are handled differently in CarcMail.
Hard bounces are permanent failures. The email address doesn’t exist, the domain isn’t accepting mail, or the address has been permanently blocked. CarcMail marks hard-bounced leads as invalid and will never send to them again.
Soft bounces are temporary failures. The recipient’s mailbox is full, the mail server is temporarily unavailable, or there’s a transient network issue. CarcMail logs the soft bounce and may retry the delivery.
Why bounce rate matters
Your bounce rate is one of the signals email providers use to judge whether you’re a legitimate sender. A high bounce rate suggests you’re emailing addresses you haven’t properly validated — a pattern common with spam senders.
If your bounce rate rises above a safe threshold, CarcMail will automatically pause your campaigns and notify you. This is a protective measure to prevent your inbox from being flagged or blocked by email providers.
CarcMail measures bounce rate over the past 30 days of sends, not your all-time history. This means a past period of high bounces does not permanently penalise you — cleaning your list and sending to valid addresses will improve your rate within a few weeks.
How CarcMail handles bounces automatically
- On hard bounce: The lead is marked “Bounced” in your leads list. No further emails are sent to that address from any campaign. This happens within minutes of the bounce notification arriving.
- On soft bounce: CarcMail logs the bounce and may retry once. If the second attempt also fails, it treats the address as a hard bounce.
- Campaign auto-pause: If your 30-day bounce rate exceeds 10%, CarcMail pauses all active campaigns and sends you a notification. You can review your list, remove problematic leads, and resume.
Reducing bounce rate
- Only import lead lists where the email addresses are from reliable sources
- Avoid purchased or scraped lists — these tend to have high rates of invalid addresses
- Use CarcMail's lead validation on import — rows flagged as invalid are excluded
- After a high-bounce period, remove all leads marked 'Bounced' from future campaigns
- Keep your lead list fresh — email addresses go stale over time, especially at companies with high turnover
Viewing bounce data
Go to Send Logs
In the sidebar, click Send Logs. You can filter by status — select Bounced to see all bounced sends.
Check individual lead status
Go to Leads and filter by status Bounced. This shows every lead that has received a hard bounce. You can export this list for cleanup.
Review your campaign bounce rate
On the campaign detail page, the Delivery stats section shows open rate, reply rate, and bounce rate for that campaign. Compare against your 30-day average.
How to confirm your bounce rate is healthy
- Send Logs shows the majority of recent sends with “Delivered” status
- Leads with “Bounced” status make up less than 5% of your imported leads
- No auto-pause notifications in the last 30 days
If CarcMail auto-pauses your campaigns due to high bounce rate, do not simply resume without cleaning your list. The same leads will bounce again, worsening the problem. Remove bounced leads and validate your list before restarting.
Common issues
| Issue | What to check |
|---|---|
| All emails from a domain are bouncing | The company may have changed their mail server or the domain may have expired. Remove those leads. |
| Bounce rate suddenly spiked | Check whether you recently imported a new list with lower-quality addresses. |
| Campaign was auto-paused | Go to Leads, filter by Bounced, export, and remove them. Then check your rate before resuming. |
Put it into practice
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